The times taken by 12 athletes to run 400 m are given in the table below.
| Athlete | A | B | C | D | E | F | G | H | I | J | K | L |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Time (s) | 45.2 | 46.9 | 46.1 | 46.2 | 45.4 | 45.1 | 47.8 | 45.4 | 45.5 | 46.1 | 46.4 | 45.7 |
Find the mean time taken.
Find the standard deviation of these times.
Find the median, the lower quartile and the upper quartile of these times.