IGCSE · Practice questions · Classifying and interpreting data

Tables that talk.

Six original Cambridge-style questions on classifying data, frequency and two-way tables, comparing two data sets and the limits of a survey.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

The method

Classify, count, read the right total, compare in context.

Classify: words are qualitative; counts are discrete; measurements are continuous.
Tally: one pass through the data, gates of five, then check the frequencies add to the total.
Two-way tables: fill any row or column with only one gap, then check the last row or column.
Fractions: the total after 'of' goes on the bottom.
Compare: one average and one spread, each in context.

Recall

[2 marks]

State whether each type of data is qualitative, discrete or continuous.

(a) The number of text messages sent in a day (b) The length of a leaf (c) The make of a phone (d) The temperature at noon

(a) discrete (counted) ✓
(b) continuous (measured) ✓
(c) qualitative (a category) ✓
(d) continuous (measured) ✓

Calculation

[3 marks]

The numbers of goals scored in 16 football matches are

2 0 1 3 1 1 0 2 4 1 2 0 1 3 1 2

(a) Make a frequency table. (b) In how many matches were more than 2 goals scored?

(a) 0 goals: 3, 1 goal: 6, 2 goals: 4, 3 goals: 2, 4 goals: 1. ✓
Check: \(3 + 6 + 4 + 2 + 1 = 16\). ✓
(b) More than 2 means 3 or 4 goals: \(2 + 1 = 3\) matches. ✓

Calculation

[3 marks]

Complete the two-way table.

	Left-handed	Right-handed	Total
Boys	4
Girls		17	20
Total	7		36

Girls left-handed: \(20 - 17 = 3\). Check left column: \(4 + 3 = 7\). ✓
Boys total: \(36 - 20 = 16\), so boys right-handed: \(16 - 4 = 12\). ✓
Right-handed total: \(12 + 17 = 29\) (check: \(36 - 7 = 29\)). ✓

Analysis

[2 marks]

Using your table from the previous question, find (a) the fraction of the boys who are left-handed (b) the percentage of the left-handed students who are girls.

(a) \(\dfrac{4}{16} = \dfrac{1}{4}\) ✓
(b) \(\dfrac{3}{7} \times 100 = 42.9\%\) (3 s.f.) ✓

Analysis

[2 marks]

In June, Town P had a median daily rainfall of 4 mm with range 9 mm. Town Q had a median of 7 mm with range 3 mm. Make two comparisons between the rainfall in the two towns.

Average: Town Q had more rain on average (higher median, \(7 > 4\)). ✓
Spread: Town Q's rainfall was more consistent (smaller range, \(3 < 9\)). ✓

Analysis

[5 marks]

A cafe records the drinks bought by its 200 customers on one Saturday.

	Hot drink	Cold drink	Total
Morning	85		120
Afternoon		48
Total			200

(a) Complete the table. (b) What percentage of the hot drinks were sold in the morning? (c) The manager says 'Afternoon customers always prefer cold drinks.' Comment on this claim.

(a) Morning cold: \(120 - 85 = 35\). Afternoon total: \(200 - 120 = 80\). ✓
Afternoon hot: \(80 - 48 = 32\). Hot total: \(85 + 32 = 117\). Cold total: \(35 + 48 = 83\) (check: \(117 + 83 = 200\)). ✓
(b) \(\dfrac{85}{117} \times 100 = 72.6\%\) (3 s.f.) ✓
(c) On this day \(\dfrac{48}{80} = 60\%\) of afternoon customers chose cold drinks, so most did. ✓
But the data come from one Saturday only (perhaps a hot day), so 'always' is not justified. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.