Week 3 Quiz Review for Math 221

B. Heard(These may not be copied, reproduced, or posted in

an online classroom without my permission. Students may download one copy for personal use.)

Week 3 Quiz Review

• Data Collection– Sampling– Census– Experiments– Simulations– Etc.

Week 3 Quiz Review

• Descriptive & Inferential Statistics– Know the difference– Descriptive - This is a set of methods to describe

data that we have collected.– Inferential - This is a set of methods used to make

a generalization, estimate, prediction or decision.

Week 3 Quiz Review

• Know the difference between Qualitative and Quantitative Data

Week 3 Quiz Review

• Types of Sampling– Random– Stratified– Cluster– Systematic– Convenience

Week 3 Quiz Review

• Populations and Samples– Parameters and Statistics

Week 3 Quiz Review

• Standard Deviation and Variance– How to calculate and mathematical relationship.– Variance is the Standard Deviation squared.– Standard Deviation is the square root of the

Variance.

Week 3 Quiz Review

• Be able to get a regression equation.• Example– Data (4, 30), (4,35), (5,36), (6,42), (8,48)

Week 3 Quiz Review

• Be able to get a regression equation.• Example– Data (4, 30), (4,35), (5,36), (6,42), (8,48)

Week 3 Quiz Review

• Be able to get a regression equation.• Example– Data (4, 30), (4,35), (5,36), (6,42), (8,48)

Week 3 Quiz Review

• Be able to get a regression equation.• Example– Data (4, 30), (4,35), (5,36), (6,42), (8,48)

This would be written as y = 3.982x + 16.70

Week 3 Quiz Review

• Use a multiple regression equation.• Plug and Chug• y = -6.5 +12a + 5.1 b where a is test score and b is

a competency score. y predicts the person’s score on a job test.

• Predict a job test score for a person who made a 50 on the test and got a 7 as a competency score.

• y = -6.5 +12(50) + 5.1 (7)• Y = 629.2

Week 3 Quiz Review

• Correlation Coefficients, also noted as “r”• Range from -1 to +1• .75 to 1 is strong• .5 to .75 is moderate• .25 to .5 is weak• 0 to .25 is very weak (closer to zero, almost none)• + would be positive correlation, - would be negative

correlation• For example, -0.58 would be moderate negative

correlation

Week 3 Quiz Review

• Be able to create a stem and leaf plot and determine descriptive statistics.• Mean• Median• Mode• Range• Variance• Standard Deviation

• Use Minitab!

Week 3 Quiz Review

• Identify Class Width• Identify Midpoint of certain classes• Identify class boundaries• Give the relative frequency• Fishing Tournament Data below is an example

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

Week 3 Quiz Review

• Class Width is 8

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

8-0 = 8, or you could havesaid 15 – 7 = 8, or counton your fingers, 0,1,2,3,4,5,6,7(There are eight numbers,don’t let it fool you)

Week 3 Quiz Review

• Midpoint of second class is 11.5

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

8+15 = 23 divided by 2 gives you 11.5

Week 3 Quiz Review

• What are the class boundaries of the third class? 15.5 and 23.5

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

Subtract .5 from the lower to get 15.5 and add .5 to the upper to get 23.5

Week 3 Quiz Review

• Give the relative frequency of all classes

Number of Fish Frequency Relative Frequency0-7 9 9/39

8-15 15 15/3916-23 12 12/3924-31 3 3/39

Total of 39

Week 3 Quiz Review

• Come see me at the “Statcave”• www.facebook.com/statcave• You DO NOT have to be a Facebook person to

see these.• If you are, become a fan.• IT IS NOT REQUIRED TO BE ON FACEBOOK. IT’S

SOMETHING I DO FOR FUN.• I post charts there because it is easy for me to

do.