1 BA 275 Quantitative 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

2 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.

3 Cyberstats Registration. Website: 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 and click on the “Course Materials” tab. Click on the CyberStats icon to start a CyberStats session.

4 CyberStats Online Assignment All 24 assignments are due at 5:00 p.m., Friday, March 17, Three attempts with instant feedback. I will keep the best scores.

5 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

6 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.

7 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%?

8 Statistical Analysis

9 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

10 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

11 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?

12 CEO Data

13 Summarizing Categorical Data