This table gives information about the distance, d d\,d km, travelled by each of 136 people to go to a music concert.
| Distance (d d\,d km) | Number of people (fff) |
|---|---|
| 40<d≤4540 < d \leq 4540<d≤45 | 6 |
| 45<d≤5045 < d \leq 5045<d≤50 | 19 |
| 50<d≤6050 < d \leq 6050<d≤60 | 53 |
| 60<d≤7060 < d \leq 7060<d≤70 | 37 |
| 70<d≤9070 < d \leq 9070<d≤90 | 15 |
| 90<d≤15090 < d \leq 15090<d≤150 | 6 |
Calculate an estimate for the mean distance.
Calculate an estimate for the standard deviation of the distances. Give your answer correct to 2 decimal places. You may use ∑fd2=552,756.25\sum fd^2 = 552,756.25∑fd2=552,756.25.
