Lesson

Read the rule, then work each example: try the setup yourself, then tap to check one step at a time.

The rules

Bars touch; the x-axis shows class boundaries; bar height = frequency.

Plot a dot at each class MIDPOINT at height f, join with lines, and start and end on the axis (0) one class before the first and after the last.

Plot cumulative frequency at each UPPER boundary; start at 0 at the first lower boundary; climb to n; never go down.

Make a cumulative column: each f added to everything above it.
Check the last total equals n.
Plot (first lower boundary, 0), then (each upper boundary, cumulative).
The curve never goes down. (The key's drawn glucose ogive misses this — see Key errors.)

Example 1 · 1.2 #10/5

Construct a histogram for the data in exercise 1 of section 1.1.

Try the setup yourself first, then tap.

Example 2 · 1.2 #20/5

Construct a histogram for the data in exercise 6 of section 1.1

Test Scores (Class)	Number of students (Frequency)
___	___
___	___
___	___
___	___

Try the setup yourself first, then tap.

Example 3 · 1.2 #30/6

Construct a frequency polygon for the data in exercise 6 of section 1.1.

Test Scores (Class)	Midpoints	Number of students (Frequency)
___	___	___
___	___	___
___	___	___
___	___	___

Try the setup yourself first, then tap.

Example 4 · 1.2 #40/6

Construct an ogive for the data in exercise 6 of section 1.1.

Step 1: Use the upper bound of each class and place them in the first column.

Step 2: The cumulative frequency for each class is determined by adding all frequencies of the previous class(es) together.

Note: The first value in the Cumulative Frequency column is the same as the first value in the Frequency column

Test Scores (Class)	Number of students (Frequency)	Cumulative Frequency
Up to ___	___	___
Up to ___	___	___
Up to ___	___	___
Up to ___	___	___

Try the setup yourself first, then tap.