Ted throws the javelin. The table gives information about the distances he threw the javelin last year.
| Distance (d d\,d metres) | Frequency |
|---|---|
| 0<d≤400 < d \leq 400<d≤40 | 25 |
| 40<d≤6040 < d \leq 6040<d≤60 | 36 |
| 60<d≤8060 < d \leq 8060<d≤80 | 14 |
| 80<d≤9080 < d \leq 9080<d≤90 | 5 |
Calculate an estimate for the mean distance.
Calculate an estimate for the standard deviation of the distribution. Give your answer correct to 1 decimal place. You may use ∑fd2=204,725\sum f d^2 = 204,725∑fd2=204,725.
