5.1 Descriptive Statistics: Some popular Displays of Data

5.1.1 Organizing Qualitative Data

Frequency and Relative Frequency Tables

A frequency distribution lists each category of data and the number of occurrences for each category

The relative frequency is the proportion (or percent) of observations within a category.

A relative frequency distribution lists each category of data together with the relative frequency of each category.


Bar Graphs

favorite color frequency
blue 10
red 3
orange 1
yellow 3
green 5
pink 3
purple 1

Bar Graphs / Bar Charts

  1. heights can be frequency or relative frequency
  2. bars must not touch
favorite color relative frequency
blue 10/26≈ 0.38
red 3/26≈ 0.12
orange 1/26≈ 0.04
yellow 3/26≈ 0.12
green 5/26≈ 0.19
pink 3/26≈ 0.12
purple 1/26≈ 0.04


Pie Charts

Pie Charts

1.should always include the relative frequency

2.also should include labels, either directly or as a legend

To the beginning of the section