The number of calls received in an hour is summarised below. The mean is 2 calls.
| Number of calls, xxx | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| Frequency, fff | 2 | 3 | 4 | 3 | 2 |
Calculate the variance.
Interpret the standard deviation in context.
278 exam-style questions on CCEA A Level Maths 2.5 Data presentation and interpretation, covering 2.5.1 Data presentation and interpretation, 2.5.2 Data presentation and interpretation, 2.5.3 Data presentation and interpretation, 2.5.4 Data presentation and interpretation, 2.5.5 Data presentation and interpretation, 2.5.6 Data presentation and interpretation, 2.5.7 Data presentation and interpretation, 2.5.8 Data presentation and interpretation, 2.5.9 Data presentation and interpretation, and 2.5 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.