9709 P52 - Nov 2022 - Q4
2410
The times taken, in minutes, to complete a word processing task by 250 employees at a particular company are summarised in the table.
| Time taken \( t \) (minutes) | \( 0 \le t \lt 20 \) | \( 20 \le t \lt 40 \) | \( 40 \le t \lt 50 \) | \( 50 \le t \lt 60 \) | \( 60 \le t \lt 100 \) |
|---|---|---|---|---|---|
| Frequency | 32 | 46 | 96 | 52 | 24 |
(a) Draw a histogram to represent this information.
From the data, the estimate of the mean time taken by these 250 employees is \( 43.2 \) minutes.
(b) Calculate an estimate for the standard deviation of these times.
