write down the easiest and hardest section of your exam. write down the easiest and hardest section...

BELL RINGER9.22.2011Write down the easiest and hardest section of your exam.

NEXT READING ASSIGNMENT: Modules 4 – 5 (pgs. 49 – 89).

DUE MONDAY, OCT. 3

Unit 2: Research Methods

AP Psychology Ms. Desgrosellier

EXPERIMENTAL METHOD

The Scientific MethodMake observations, form theories, and

then refine their theories in the light of new observations.

Scientific theory: an explanation using an integrated set of principles that organizes and predicts observations.

A good theory organizes the large amount of observations and information into a short list of principles

It must produce a testable predictions.

The Controlled ExperimentWhat are the parts of a psychological experiment?

Experiment: the researcher systematically manipulates a variable under controlled conditions, and observes the response.

The Controlled ExperimentWhat are the parts of a psychological experiment?

Experiment: the researcher systematically manipulates a variable under controlled conditions, and observes the response.

The ONLY way to prove cause and effect.

The Controlled ExperimentHypotheses: predictions of how two or more factors are likely to be related.

The factor the researcher manipulates is the independent variable (IV).

The Controlled ExperimentThe dependent variable (DV) is

the behavior or mental process that is being measured, the factor that may change as a result of manipulation of the independent variable.

If the dependent variable changes when only the independent variable is changed, the researcher can conclude that the change in the IV caused the change in the DV.

The Controlled ExperimentExample: If we want to do an experiment to find out if smoking causes cancer:What are potential

hypotheses?What is our IV?What is our DV?

The Controlled ExperimentExample: If we want to do an experiment to find out if smoking causes cancer:Hypotheses: Smoking causes

cancer, etc.IV: Smoking or not smoking.DV: tests to see if you have

cancer.

The Controlled ExperimentExample: If we want to do an experiment to see what the effect of drinking caffeine and math ability:What are potential

hypotheses?What is our IV?What is our DV?

The Controlled ExperimentExample: If we want to do an experiment to see what the effect of drinking caffeine and math ability:Hypotheses: Drinking caffeine

will improve math abilities; drinking caffeine will decrease math abilities.

IV: CaffeineDV: Math test

The Controlled ExperimentPopulation: all of the individuals in the group that the experiment applies to.

e.g. If I am studying the effect of sports on high school students’ GPAs, who is my population?

e.g. If I am researching how much pop people in the United States drink, who is my population?

The Controlled ExperimentIt’s difficult to study a whole population, so researchers use samples.

Sample: a subgroup of the population

Samples save money and time.

The Controlled ExperimentIdeal samples must be:

Representative of the population (e.g. if I want to study the effect of eating candy on men, would women be a good sample?)

Large (the bigger the sample, the more likely it is to represent the population.)

The Controlled ExperimentIdeal samples must be:

Random (everyone in the population has an equal chance of being selected.)

Random selection: everyone in the population has the same chance of being chosen.

The Controlled ExperimentWhen our samples involve people, they are called participants, or less commonly, subjects.

The Controlled ExperimentThe sample is then randomly assigned into one of two groups:

Experimental Group: the sample that receives the treatment.

Control Group: the sample that does not receive the treatment.

Copy this table down!

IV

Experimental

DV

No IV (placebo)

Control

DV

The Controlled Experimente.g. Which group is which? In a study, one group receives an experimental drug and one receives a sugar pill.

e.g. In a study of how playing an instrument effects learning, one group plays an instrument and one does not.

The Controlled ExperimentThis is called a between-subjects design: participants in the experimental and control groups are different individuals.

The Controlled ExperimentSo what is a within-subjects design?

A research design that uses each participant as his or her own control.

e.g. To see if tutoring improves test scores, a group of students is not tutored for the first semester and then tutored for the second.

The Controlled ExperimentOperational definition: describes the specific procedure used to determine the presence of a variable.

Specific and observable way to define variables.

The Controlled ExperimentOperational definitions make replication possible!

Replication: repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances.

The Controlled ExperimentDiet Coke vs. Regular Coke

Which one (if either) will float?

Hypotheses?

IV?

DV?

The Controlled ExperimentDiet Coke vs. Regular Coke

Why does Diet Coke float? Regular Coke is more dense (probably because of the sugar content) and sinks. Diet is less dense!

Bell Ringer9.26.2011

Correct the following “homework” by Ms. Desgrosellier. What’s wrong with the experiment?:

I am doing an experiment because I believe that high school students who take AP Psychology students are smarter than their peers. My IV is taking AP Psych and my DV is not taking AP Psych. My population is all US citizens, so a sample of 10 students from Uplift HS is an ideal sample. I will divide my participants into two groups and compare them to each other, so this is a within subjects design.


NEXT READING ASSIGNMENT: Modules 4 – 5 (pgs. 49 – 89).

DUE MONDAY, OCT. 3

The Controlled ExperimentCreate an operational definition:

With your group, create an operational definition for an emotion.

It must be OBSERVABLE!

e.g. If I was describing surprise:Wide eyes, open mouth, verbal

exclamations or shocked silence.

The Controlled ExperimentWhy is randomness so important?

To eliminate bias and control confounding variables.

Confounding variables: differences between the experimental and control groups NOT caused by the independent variable.

The Controlled ExperimentConfounding variablese.g. You do an experiment to find

out if drinking orange juice in morning helps students stay awake.

Half your students drink juice and half do not, and then you count the sleeping students in 1st period.

The half that drinks the juice stays awake.

What are some confounding variables?

The Controlled ExperimentConfounding variablesEating breakfastAmount of sleepGenderStudents’ academic abilityetc.

The Controlled ExperimentWhen we have a lot of control, we can determine cause and effect.

EXPERIMENTS ARE THE ONLY WAY TO DETERMINE CAUSE AND EFFECT!!!

Eliminating Confounding Variables

experimenter bias (experimenter expectancy effect): a phenomenon that occurs when a researcher’s expectations or preferences about the outcome of a study influence the results obtained.


e.g. If you think that the drug in your study works really well, you might ask participants who took the drug, “You feel better, don’t you?”

e.g. If you think that watching TV negatively effects grades, you might unconsciously put all the lower level students into the TV group (experimental group) – note: this is without random assignment.


e.g. even smiling at one group and not another can effect the results – like if you think that playing sports makes students nicer, you might smile at the athletes and not smile at the non-athletes, affecting their behavior.


demand characteristics: clues participants discover about the purpose of the study, including rumors they hear about how they should respond.

e.g. if you have two groups coming in to do a study, and the first group tells the second everything that’s going to happen.

e.g. if you somehow indicate that one group is only receiving a placebo (e.g. “It doesn’t really matter when you take your pill, or even if you forget!”).


To control for demand characteristics, researchers use two methods:

single-blind procedure: a research design in which the participants don’t know which treatment group – experimental or control – they are in.


To control for demand characteristics, researchers use two methods:

double-blind procedure: a research design in which neither the experimenter nor the participants know who is in the experimental group and who is in the control group.

How would we do this?

e.g. assign numbers; a second experimenter, etc.


Placebo: an imitation treatment usually used in a drug study.

e.g. a sugar pill instead of a real drug.

placebo effect: when subjects believe that the treatment will be effective and they think they experience an improvement in health or well-being, even though they did not receive the actual drug.


“Placebo effect” now refers to any case when the experimental participants change their behavior without of any kind of experimental manipulation.

Counterbalancing: a procedure that assigns half the subjects to one of the treatments first and the other half of the subjects to the other treatment first.

DO NOW:Identify any bias or confounding

variables in the following experiment.

I think that studying your notes every night will increase your test scores in Psychology. I split my class into two groups: the half that scored the highest on the last exam and the half that scored the lowest. Then, I have my highest scoring half study every night, while my lowest only studies before our next test. I then compare their test scores and find that my hypothesis is correct: those who studied every night had higher test scores!

DO NOW:Identify the bias, confounding variables, demand

characteristics and/or placebo effect.

I’m doing a study on the effect of eating cupcakes on intelligence. My participants do not know what I am studying. Half of them will eat a cupcake every morning for a week and half will eat a plain bagel. At the end of the week I will give them an IQ test. I make sure to smile at the cupcake group when they are eating, but not at the bagel group. One participant thinks that “bagels” are my experimental condition, and they study extra hard every night and end up with the highest test score. However, overall my cupcake group has the highest average.

Quasi-Experimental Research

Quasi-experimental research: similar to controlled experiments, but participants are not randomly assigned.

e.g. male vs. female; young vs. old; students in period 2 vs. period 8

Because of confounding variables, quasi-experiments DO NOT determine cause and effect.

CORRELATIONAL RESEARCH

Experiments cost time, money, and are not very generalizable.

Correlational methods look at the relationship between two variables without establishing a cause and effect relationship.

The goal is to determine to what extent one variable predicts the other.

Naturalistic Observation

observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.

e.g. observing animals in the wild; unobtrusively videotaping parent-child interactions

N.O. has revealed that chimpanzees sometimes use tools like humans (using a stick to get to termites).

Good for generating ideas for other research.

Survey Method

Researchers use questionnaires or interviews to ask a large number of people questions about their behaviors, thoughts, and attitudes.

Participants should be representative of the population.

How do we get a sample to be representative?

RANDOM SAMPLING!

DO NOW9.27.2011Identify the bias, confounding variables, demand

characteristics and/or placebo effect.

I’m doing a study on the effect of eating cupcakes on intelligence. My participants do not know what I am studying. Half of them will eat a cupcake every morning for a week and half will eat a plain bagel. At the end of the week I will give them an IQ test. I make sure to smile at the cupcake group when they are eating, but not at the bagel group. One participant thinks that “bagels” are my experimental condition, and they study extra hard every night and end up with the highest test score. However, overall my cupcake group has the highest average.

Survey Method

Accuracy of data is an issue because people sometimes distort their answers or fail to recall information correctly.

The data collected is good for generating ideas for other research.

Survey Method

Ex post facto studies: retrospective studies that look at an effect to find the cause.

Survey Method

e.g. In the 1970s, researchers noticed that a lot of babies were being born with deformed limbs, and they asked the mothers a lot of questions.

The found the strongest relationship between the mothers was the drug thalidomide during the pregnancies.

Controlled experiments in the lab with rodents verified that the drug caused abnormal limb development in the babies of animals.

Test Methods

Tests are procedures used to measure attributes of individuals at a particular time and place.

Like surveys, they can be used to gather huge amounts of information relatively quickly and cheaply.

Results of tests can be used for correlational analysis or for generating ideas for other research.

Test Methods

Both surveys and tests need to be reliable and valid.

Reliability: consistency or repeatability.

i.e. subjects should answer questions the same way on two different occasions.

e.g. If I give you a personality test in the fall and another in the spring, a reliable test should give me the same results both times.

Test Methods

Validity: the extent to which an instrument measures or predicts what it is supposed to.

e.g. Algebra questions would not be a valid way to measure what you learned in history class.

e.g. Asking questions about the frequency of showering to indicate cooking ability is not valid.

Reliability and Validity

CASE STUDY

Case study: an in-depth examination of a specific group or single person.

Typically includes interviews, observations and test scores.

It is most helpful when studying complex or rare phenomena.

Case studies CANNOT prove cause and effect.

CASE STUDY

They can help generate hypotheses for future studies.

e.g. Phineas Gage, a man who got a metal rod shoved through his skull and survived was studied to figure out what part of his personality was changed due to the loss of brain matter.

Genie, an abused girl who was locked up for 13 years was studied to discover if language could be acquired at any time or if there was a critical period for acquisition.

Illusory Correlations:

The perception of a relationship where none exists.

When we believe there is a relationship between two things, we are likely to notice and recall instances that confirm our belief.

We also forget or ignore instances that disprove our belief.

Shark attack!

For example, a study published said that there is a correlation between ice cream sales and shark attacks in Southern California.

Potential relationships:Shark attacks cause people to eat ice creamEating ice cream causes sharks to attack

you

Third factor? They aren’t related at all! Spurious relationship. What is the actual cause?

Illusory Correlations:

Illusory correlations come from our natural want to make sense of our world.

Even given random data, we look for order, for meaningful patterns.

Random sequences often don’t look random, and therefore get over-interpreted

Find your birthday in pi

http://angio.net/pi/piquery

ELEMENTARY STATISTICS

Statistics: a field that involves the analysis of numerical data about representative samples of populations.

Quantitative and qualitative data can be turned into numbers to be analyzed.


There are four scales that data can be separated on.

Nominal: numbers used to name something; they have no intrinsic meaning.e.g. Gender; girls = 1, boys = 0

Ordinal: numbers that can be ranked and can be put in order.Winners in a race can be ranked 1st,

2nd, 3rd, etc.


Interval: there is a meaningful difference between each of the numbers.e.g. temperature

Ratio: when a meaningful ratio can be made with two numbers; has an absolute 0.e.g. weight, volume, and distance


What scale are the following data on?

GPA

Grade level (9th, 10th, 11th, 12th)

Degrees in Celcius

Number of absences per year

DO NOW:Dr. Buns wants to know if there is a relationship

between the goals scored at a high school soccer game and the school’s average ACT score. He goes to only Uplift soccer games and records how many goals are scored. He then compares the scores to the highest reported ACT score and finds that more goals indicates higher average ACT scores.

Find the mean, median, and mode of the following data set of soccer goals scored: 3, 5, 1, 3, 0, 7, 2

Identify one problem with this study.

DO NOW:First, arrange the scores in order from

low to high:

0, 1, 2, 3, 3, 5, 7

Mode: The score that occurs most frequently = 3

Median: The middle score when arranged in order = 3

Mean: total of scores added up and divided by the number of scores: 21/7=3

DO NOW:Dr. Debrah wants to know which gender is

affected by caffeine the most. She divides her participants randomly into two groups including both men and women. Group A drinks caffeinated coffee while Group B drinks decaf. She then has each participant juggle and times how long they can keep 3 balls in the air. The times in seconds for several participants can be found below.

What kind of research is this? (case study, etc.)

What kind of data is gender? What about time? (Nominal, Ordinal, Interval or ratio?)

What are the mean, median and mode of the the data set (in seconds)?

10, 5, 3, 2, 5

BELL RINGER9.28.2011

Identify the type of research being described below:

I give a questionnaire to all seniors to find out what colleges they are applying to.

I want to study if taking AP Psych 1st period or 3rd period will help you learn better.

I notice that a lot of my students are getting taller and taller each year. I interview them about their nutrition and exercise a child to find a cause for this.

I want to know which grade at Uplift has more “upstanders” so I go to each lunch and watch for helpful, respectful behavior and record it.

Bell Ringer9.30.2011Dr. King wants to know which gender is affected

by caffeine the most. She divides her participants randomly into two groups including both men and women. Group A drinks caffeinated coffee while Group B drinks decaf. She then has each participant juggle and times how long they can keep 3 balls in the air. The times in seconds for several participants can be found below.

What kind of research is this? (case study, etc.)

What kind of data is gender? What about time? (Nominal, Ordinal, Interval or ratio?)

What are the mean, median and mode of the the data set (in seconds)?

10, 5, 3, 2, 5

Descriptive Statistics

Descriptive statistics: numbers that summarize a set of research data obtained from a sample.

In general, descriptive statistics describe sets of interval or ratio data.


frequency distribution: an orderly arrangement of scores indicating the frequency of each score or group of scores.


This can be represented by a histogram, better known as a bar graph.


frequency polygon: a line graph that replaces the bars with single points and connects the points with a line (a line graph).

Measures of Central Tendency

central tendency: description of the average or most typical scores for a set of research data or distribution.


Mode: the most frequently occurring score in a set of research data.

If two scores appear most frequently, the distribution is bimodal.

If more than two appear most frequently, the distribution is multimodal.

The least used measure, but can be useful to provide a quick and easy measure, especially when the data has not been ordered.


Find the mode:

The number of points scored in Uplift soccer games is listed below.

3, 5, 1, 3, 0, 7, 2


Median: the middle score when the set of data is ordered by size.

For an odd number of scores, the median is the middle one.

For an even number of scores, the median is halfway between the two middle scores.

Less sensitive to extreme data points, but doesn’t take into account all the information in the data points.


Find the median:


3, 5, 1, 3, 0, 7, 2


Mean: the arithmetic average of the set of scores.

Add up all the individual scores and divide by the total number of scores.

The generally preferred measure because it takes into account all the data points.

However it is very sensitive to extremes; it is pulled in their direction.


Find the mean:


3, 5, 1, 3, 0, 7, 2


All of these are the same score in symmetrical distributions.

normal distribution: a symmetric, bell-shaped curve that represents data about how many human characteristics are dispersed in the population.


skewed: distributions where most of the scores are squeezed into one end.

In very skewed distributions, the median is a better measure than the mean.

Measures of Variability

Variability: describes the spread or dispersion of scores for a set of research data or distribution.


Range: the largest score minus the smallest.A rough measure of dispersion.

Variance and Standard Deviation indicate the degree to which scores differ from each other and vary around the mean value of the set.

They both indicate how much scores group together and how dispersed they are.


Variance: determined by computing the difference between each value and the mean, squaring the difference between each value and the mean, summing the squared difference, then taking the average of the sum of squared differences.


Standard Deviation (SD): The square root of variance.

It must fall between 0 and half the value of the range.

If SD approaches half the value of the range, scores vary greatly from the mean.

Bell Ringer10.3.2011HAVE YOUR READING NOTES OUT TO BE CHECKED.

Time (minutes) for an Uplift football player to

run a mile

# of players Time in minutes

1 153 45 56 88 6What is the range of this data set?

Sketch a histogram to represent this data (it doesn’t have to be perfect).

Is this data skewed? If so, which way (positive or negative)?

Correlation

standard score (z score): enable psychologists to compare scores that are initially on different scales.

Computed by subtracting the mean raw score of the distribution form the raw score of interest, then dividing the difference by the standard deviation of the distribution of raw scores.

Correlation

percentile score: indicates the percentage of scores at or below a particular score.

Range from 1 to 99.

If you score at the 90th percentile, 90% of the scores are the same or below yours.

Correlation

Correlation coefficient: a statistical measure of the degree of relatedness or association between two sets of data, X and Y.

Varies from -1 to +1.

-1: perfect negative correlation (as one variable increases, the other decreases).

+1: perfect positive correlation (as one variable increases, the other also increases; as one variable decreases, the other also decreases).

0: No relationship

Correlation

Correlation is NOT causation. It only indicates a relationship!

scattergrams (scatterplots): visually indicate the strength and direction of correlations.

Correlation

Correlation

Explain each of the following correlations:

There is a positive correlation between height and shoe size.

There is a negative correlation between weight and amount of candy eaten.

There is no correlation between number of showers per week and cooking ability.

Correlation

Explain each of the following correlations:

There is a correlation of –0.85 between number of hours spent watching TV and GPA.

There is a correlation of –0.01 between shirt color worn and scores on the ACT.

There is a correlation of +0.95 between smoking cigarettes and instances of lung cancer.

Inferential Statistics

Used to interpret data and draw conclusions.

Tell psychologists whether or not they can generalize from the chosen sample to the whole population (i.e. if the sample actually represents the population).


Use rules to evaluate the probability that a correlation or a difference between groups reflects a real relationship and not just the operation of chance factors on the particular sample that was chosen for study.

Statistical significance (p): is a measure of the likelihood that the difference between groups results from a real difference between the two groups rather than from chance alone.


Results are likely to be statistically significant when there is a large difference between the means of the two frequency distributions, when their SDs are small, and when the samples are large.


The lower the p-value, the less likely the results were due to chance.

p < .05 is the usual benchmark for most psychological studies (meaning there is less than a 5% chance that the results are do to random variation.

Some researchers prefer to use p < .01.


Meta-analysis: a statistical way to combine the results of individual research studies to reach an overall conclusion.

Bell Ringer10.4.2011I want to study the relationship between

the amount of sleep students get and their GPA. I survey all the students at Uplift Community HS and find that there is a +0.99 correlation between amount of sleep and GPA, and a p value < .05.

What does the correlation coefficient tell us?

What does the p value tell us? Are our results statistically significant?

ETHICAL GUIDELINES

In the 1970s, Stanley Milgram’s studies in which people believed that they were delivering deadly electric shocks to other people were highly publicized.

ETHICAL GUIDELINES

The American Psychological Association (APA) then strengthened their ethical guidelines regarding research design, implementation, and practice.

They prevent unnecessary deception and pain to humans and other animals, and protect confidentiality.

ETHICAL GUIDELINES

All public and private institutions have Institutional Review Boards (IRB) that must approve of all research conducted within their institutions.

They protect participants by requiring researchers to obtain signed informed consent agreements from all participants.

ETHICAL GUIDELINES

These statements describe procedures, risks, benefits, and the right of the participant not to participate, or to withdraw from the research study without penalty at any their willingness to participate.

Participants cannot be deceived about significant aspects that would affect their willingness to participate.

ETHICAL GUIDELINES

After they finish participating, they are debriefed about the research (i.e. the nature, results, and conclusions of the research are revealed).

ETHICAL GUIDELINES

Psychologists who conduct research involving other animals must treat them humanely.

Acquire, care for, use, and dispose of animals properly.

Make efforts to minimize their discomfort, infection, illness, and pain.

ETHICAL GUIDELINESPlease read the following scenarios

carefully. Within each scenario is an ethical problem or dilemma. Identify and discuss the ethical problems with each scenario.

Once you have identified the ethical problem within the scenario, explain how you would change or revise the design to make it ethically acceptable.

Please think carefully about each scenario and if possible, provide a solution.

ETHICAL GUIDELINESAn experiment was conducted to

test a new drug for depression. For the experimental group, Dr. Sneaky wrote a new prescription for depression without discussing it with the patients. For the control group, Dr. Sneaky prescribed their normal prescription.

What is wrong with this scenario?

ETHICAL GUIDELINESDr. Mad conducted a study entitled

“Emotion in the Media” to test the effects of anger. The participants were shown a video containing infuriating materials. The participants were then given a questionnaire to complete. Participants were told they could leave upon completion of the questionnaire. Dr. Mad thanked the participants for their time.


ETHICAL GUIDELINESIn an introductory psychology

course, students were offered extra credit for their semester grade. In order to receive the credit, they had to participate in a AP Psychology research project. They were not given any other alternative opportunities to receive extra credit.



Read the following scenario and identify as many ethical issues as you can:

Professor Evil wants to know how electric shocks affect mood. He selects 50 participants and splits them randomly into two groups. Before the start of the study, he tells his participants that if they leave early, he will come to their house and steal something. He attaches shock collars to half his group and shocks them every 5 minutes. He then gives them a survey about their mood. When they’re done, he let’s them go with a high five and gives them no additional information.

AP Psychology ResearchWe are going to do some

simple psychological research!

Split into groups of 4.

We will be doing a naturalistic observational study.

Choose something you want to observe for.

Create your operational definitions.

AP Psychology ResearchCollect data this week.

You will need to calculate all measures of central tendency.

You must report any ethical issues, confounding variables, bias, etc.

Prepare to present findings to class next week.


Read the following scenario and identify as many problems as your can (there are several):

Dr. Jones is doing a study to find out if his new drug makes people smarter. His population is all people in the USA. He picks 10 students from Uplift and puts boys in his experimental group and girls in his control group. Before the study starts, he tell the patients that they will be taking a vitamin everyday to increase their health (secretly the drug). After taking the drug every day for a week, Dr. Jones has her participants finger paint a picture, which she then uses to score their intelligence. When the study is done, she gives each participant a cookie as a good-bye gift.


Read the following scenario and answer the questions that follow.

Professor Owens does a research project on whether or not eating hot chips affects the intelligence of US high school students. She randomly selects 50 Uplift students and randomly assigns them to either eat chips once a day before school or abstain from eating them all together. After a week of this diet, she gives them an intelligence test. Professor Owens finds that there is a –0.97 correlation and a p < 0.45.

What is the population? The sample?What the correlation coefficient mean?What does the p-value tell us?

AP Psychology ResearchSit with your research team

and prepare to present preliminary data to Ms. Desgrosellier.

Keep in mind any confounding variables and any other issues that might have occurred.

AP Psychology ResearchSit with your research team and prepare to present your projects to your classmates.

When you go up to present, give Ms. Desgrosellier your rubric AND all of your data collection sheets.

Groups not ready to present today will be considered late and will lose an additional 10% off their project grade.


Read the following description of an experiment and identify the independent variables, the dependent variable, and create a control group for the study.

A student hypothesizes that high school students consuming different kinds of pizza before a math test will perform differently. A study to test the hypothesis finds that with veggie pizza, performance is best 2 hours after eating it, whereas with pepperoni pizza, performance is better 3 hours after eating it.

FRQ Review

Name all the kinds of psychological research that can be done.

Name a strength for each.

Name a drawback or weakness for each.

Think about how each method could be used to study the relationship between taking a new drug and intelligence.


The variance of a data set is 81. What is the standard deviation?

Look at the following data set; is the standard deviation large or small?1, 20, 60, 100

Look at the following data set; is the standard deviation large or small?100, 101, 102, 103

#27If the correlation between the physical weight

and reading ability of children is +0.85, this would indicate that:a) there is very little statistical relationship

between weight and reading ability among children.

b) low body weight has a negative effect on the reading abilities of children.

c) better reading ability is associated with greater physical weight among children.

d) body weight has no causal influence on the reading abilities of children.

e) weight is a causal variable dependent on reading ability.

#28During the past month, Zara and Ivan each read 2 books, but George read 9, Ali read 12, and Marsha read 25. The median number of books read by these individuals wasa) 2.b) 5.c) 8.d) 9.e)10.

#29A p – value of <.05 indicates that there is aa) 50% chance that the results are

due to random variation.b) 5% chance that the results are due

to random variation.c) 5% chance that the results are not

due to random variation.d) 50% chance that the results are

not due to random variation.e) correlation of < 5.


Choose a research method.

Name a strength

Name a weakness

How could you use that research method to study the relationship between eating hot chips and intelligence?


Reflect on your Unit 2 exam – what were you best at?

What was most difficult about the exam (multiple choice and FRQ)?

What will you do to be better prepared for the next exam?

write down the easiest and hardest section of your exam. write down the easiest and hardest section...

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