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BA 275Quantitative Business Methods

Housekeeping Introduction to Statistics

Elements of Statistical Analysis Concept of Statistical Analysis

Exploring Data Types of Data (Categorical vs. Numerical) Summarizing Data Using Graphical Methods

Agenda

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Weekly Quizzes

Weekly quizzes will be given at the end of the lecture on Wednesdays in class.

Questions are from topics covered on Monday of the same week and Wednesday of the previous week.

Need a calculator. There will be 20 minutes for each quiz

session. One lowest quiz will be dropped.

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Cyberstats

Registration. Website: http://www.thomsonedu.com/thomsonnow. School name: Oregon State University Bus Stats Content Access code: in the textbook Course Key code: section-specific, see syllabus.

Taking a Cyberstats session. Go to http://www.thomsonedu.com/thomsonnow and click on the “Course Materials” tab. Click on the CyberStats icon to start a CyberStats session.

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CyberStats Online Assignment

All 24 assignments are due at 5:00 p.m., Friday, March 17, 2006.

Three attempts with instant feedback. I will keep the best scores.

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Definition

“Statistics” is the science of data.

It involves collecting, classifying, summarizing, organizing, analyzing,

and interpreting numerical information.

We will learn how to make

based on data

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Fundamental Elements of Statistics

A population is a set of units (usually people, objects, transactions, or events) that we are interested in studying. It is the totality of items or things under consideration.

A sample is a subset of the units of a population. It is the portion of the population that is selected for analysis.

A parameter is a numerical descriptive measure of a population. It is a summary measure that is computed to describe a characteristic of an entire population.

A statistic is a numerical descriptive measure of a sample. It is a summary measure calculated from the observations in the sample.

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Example

A manufacturer of computer chips claims that less than 10% of his products are defective. When 1000 chips were drawn from a large production, 7.5% were found to be defective. What is the population of interest? What are the sample, parameter and statistic? Does the value 10% refer to the parameter or

to the statistic? How about the value 7.5%?

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Statistical Analysis

POPULATION

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Types of Data

Numerical (Quantitative) Data Regular numerical observations. Arithmetic

calculations are meaningful. Age Household income Starting salary

Categorical (Qualitative) Data Values are the (arbitrary) names of possible

categories. Gender: Female = 1 vs Male = 0. College major

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Example

For each of the following examples of data, determine the type. The number of miles joggers run per week The starting salaries of our business students The months in which a firm’s employees

choose to take their vacations The final letter grades received by students in

a statistics course

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Example

A sample of shoppers at a mall was asked the following questions. Identify the type of data each question would produce. What is your age? How much did you spend? What is your marital status? Rate the availability of parking: excellent,

good, fair, or poor How many stores did you enter?

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CEO Data

NO AGE SALARY EDUCATION1 53 145 Bachelors 2 36 291 Masters 3 48 659 Doctorate 4 53 298 Masters 5 46 250 Doctorate 6 50 291 Bachelors 7 59 296 Bachelors 8 48 388 Masters 9 43 621 Masters

10 45 58 Bachelors

: : : :: : : :: : : :

54 55 736 Bachelors 55 51 368 Bachelors 56 58 217 Bachelors 57 44 206 Bachelors 58 51 536 Masters 59 70 213 Masters 60 43 573 Bachelors

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Summarizing Categorical Data

Barchart for Degree

freq

uenc

y

0

5

10

15

20

25

Bachelors Doctorate Masters None

Piechart for Degree

DegreeBachelorsDoctorateMastersNone

41.67%

16.67%

36.67%

5.00%

Frequency Table for Degree

---------------------------------------------------------------- Relative Cumulative Cum. Rel.Class Value Frequency Frequency Frequency Frequency---------------------------------------------------------------- 1 Bachelors 25 0.4167 25 0.4167 2 Doctorate 10 0.1667 35 0.5833 3 Masters 22 0.3667 57 0.9500 4 None 3 0.0500 60 1.0000----------------------------------------------------------------