Business 90: Business Statistics Professor David Mease Sec 03, T R 7:30-8:45AM BBC 204 Lecture 3 = Start Chapter “Presenting Data in Tables and Charts” (PDITAC) Agenda: 1) Go over Homework 1 2) Lecture over first part of Chapter PDITAC 3) Take quiz over Homework 1

Homework Assignment Homework #1: Due Tuesday, February 2 1) Read the chapter entitled “Introduction and Data Collection” 2) In that chapter do textbook questions 2, 3, 8(b), 14 (skip a), 16 (skip a), 18 (Note: Answers to textbook questions with even numbers are given in the chapter. Also, you will need to use Table 1 in the back of the book.)

Presenting Data in Tables and Charts Statistics for Managers Using Microsoft® Excel 4th Edition Presenting Data in Tables and Charts

Chapter Goals After completing this chapter, you should be able to: Create an ordered array Construct and interpret a frequency distribution, histogram, and polygon for numerical data Construct and interpret a cumulative percentage distribution and ogive for numerical data Create and interpret contingency tables, bar charts, and pie charts for categorical data Create and interpret a scatter diagram and a least squares regression line (in other chapter p. 387-398) Describe appropriate and inappropriate ways to display data graphically

Organizing and Presenting Data Graphically Data in raw form are usually not easy to use for decision making Some type of organization is needed Table Graph

Example: Below are Bus 90 midterm exam scores. Describe this data. 92 60 83 36 62 65 80 88 50 63 92 64 84 89 83 80 88 91 90 84 71 77 25 92 49 88 54 51 59 41 71 53 69 68 68 57 60 90 66 50

The Ordered Array A sorted list of data: Shows range (min to max) Provides some signals about variability within the range May help identify outliers (unusual observations) If the data set is large, the ordered array is less useful

In class exercise #4: Construct the ordered array for the exam scores. Now describe this data. (It’s easier now!)

Tabulating Numerical Data: Frequency Distributions What is a Frequency Distribution? A frequency distribution is a list or a table containing class groupings (categories or ranges within which the data fall) and the corresponding frequencies with which data fall within each grouping or category

Why Use Frequency Distributions? A frequency distribution is a way to summarize data The distribution condenses the raw data into a more useful form and allows for a quick visual interpretation of the data

Class Intervals and Class Boundaries Each class grouping has the same width Determine the width of each interval by Use at least 5 groupings Class boundaries never overlap Round up the interval width to get desirable endpoints

In class exercise #5: Construct a frequency distribution for the exam scores beginning at 20 and ending at 100 using 8 intervals.

Graphing Numerical Data: The Histogram A graph of the data in a frequency distribution is called a histogram The class boundaries (or class midpoints) are shown on the horizontal axis the vertical axis is either frequency or percentage Bars of the appropriate heights are used to represent the number of observations within each class

In class exercise #6: Construct a frequency histogram for the exam scores.