CAMBRIDGE COLLEGE LIMA IGCSE MATHS

EXTENDED PROGRAMME

Statistics Worksheet 3 Histograms

Name: Set:

By the end of this worksheet you should be able to:

a. Identify the difference between discrete and continuous data.

b. Interpret grouped frequency tables.

c. Construct and interpret histograms with equal and unequal intervals.

d. Understand that for a histogram it is the area of the column that represents the frequency.

e. Use and apply the equation: Frequency Density = Frequency

Class width

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Discrete data in a Frequency Table Number of goals scored in 26 games Number of goals scored

in a game 0 1 2 3 4

Frequency (Number of games)

5 3 10 6 2

In this case, the data is discrete as the number of goals scored has to be a whole number and can be shown in a Bar Chart.

Continuous data and Grouped Frequency Tables

The mass of an orange doesn't jump from 50 grams to 51 grams suddenly, it increases continuously. We have to use inequalities to describe the mass of the oranges. The masses are grouped together in classes in a Grouped Frequency Table. The classes don't always have the same width. We display the results as a Histogram. In a Histogram 1. The bars are joined together. 2. The bars can be of varying width. 3. The frequency of the data is represented by the area of the bar and not by the height as in a bar chart. 4. The vertical axis is named Frequency density, not Frequency. 5. Frequency Density = Frequency Class Width

Class width Frequency Density