Descriptive Statistics: Tabular and Graphical Presentations

chapter 2
Chapter 2 Descriptive Statistics: Tabular and Graphical Presentations

Learning Objectives

1. Learn how to construct and interpret summarization procedures for qualitative data such as : frequency and relative frequency distributions, bar graphs and pie charts.

2. Learn how to construct and interpret tabular summarization procedures for quantitative data such as: frequency and relative frequency distributions, cumulative frequency and cumulative relative frequency distributions.

3. Learn how to construct a dot plot, a histogram, and an ogive as graphical summaries of quantitative data.

4. Learn how the shape of a data distribution is revealed by a histogram. Learn how to recognize when a data distribution is negatively skewed, symmetric, and positively skewed.

5. Be able to use and interpret the exploratory data analysis technique of a stem-and-leaf display.

6. Learn how to construct and interpret cross tabulations and scatter diagrams of bivariate data. Solutions:

1.
|Class |Frequency |Relative Frequency |
|A |60 |60/120 = 0.50 |
|B | 24 |24/120 = 0.20 |
|C | 36 |36/120 = 0.30 |
| |120 | 1.00 |

2. a. 1 - (.22 + .18 + .40) = .20

b. .20(200) = 40

c/d.
|Class |Frequency |Percent Frequency |
|A |.22(200) = 44 | 22 |
|B |.18(200) = 36 | 18 |
|C |.40(200) = 80 | 40 |
|D |.20(200) = 40 | 20 |
|Total |200 |100