Topics · Edexcel GCSE Maths (1MA1)

Histograms with unequal class widths

Higher only

In a histogram the area of a bar is the frequency, not its height. Read this one.

Exam-style questionNon-calculator3 marks

The histogram shows information about the times, $t$ minutes, that some people took to finish a puzzle.

Work out an estimate for the number of people who took between 15 and 30 minutes.

See why

16 people took between 20 and 40 minutes. How tall should that bar be?

Bar height (frequency density)3.2

Area = 3.2 × 20 minutes = 64 people. Too many.

If the height showed 16 people, this one bar would be off the top of the chart, and the widest class would look the most crowded.

New contextNon-calculator2 marks

In a histogram, the bar for the class $30 < w \le 45$ has a frequency density of 2.4

How many values are in this class?

Histograms with unequal widths

Short hands-on steps, then exam questions on this topic.

Specification S3 (Higher content): construct and interpret histograms with unequal class intervals.
Higher tier only.
Pearson's examiners report students reading a bar's height as its frequency.