4. The table shows information about the time, \(t\) minutes correct to the nearest minute, taken by 50 people to complete a race.
| Time (minutes) | \(t \leqslant 27\) | \(28 \leqslant t \leqslant 30\) | \(31 \leqslant t \leqslant 35\) | \(36 \leqslant t \leqslant 45\) | \(46 \leqslant t \leqslant 60\) | \(t \geqslant 61\) |
| Number of people | 0 | 4 | 28 | 14 | 4 | 0 |
- In a histogram illustrating the data, the height of the block for the \(31 \leqslant t \leqslant 35\) class is 5.6 cm . Find the height of the block for the \(28 \leqslant t \leqslant 30\) class. (There is no need to draw the histogram.)
- The data in the table are used to estimate the median time. State, with a reason, whether the estimated median time is more than 33 minutes, less than 33 minutes or equal to 33 minutes.
- Calculate estimates of the mean and standard deviation of the data.
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