8 The stem-and-leaf diagram shows the age in completed years of the members of a sports club.
\section*{Male}
\begin{table}[h]
\captionsetup{labelformat=empty}
\caption{Female}
| 8876 | 1 | 66677889 |
| 76553321 | 2 | 1334578899 |
| 98443 | 3 | 23347 |
| 521 | 4 | 018 |
| 90 | 5 | 0 |
\end{table}
Key: 1 | 4 | 0 represents a male aged 41 and a female aged 40.
- Find the median and interquartile range for the males.
- The median and interquartile range for the females are 27 and 15 respectively. Make two comparisons between the ages of the males and the ages of the females.
- The mean age of the males is 30.7 and the mean age of the females is 27.5 , each correct to 1 decimal place. Give one advantage of using the median rather than the mean to compare the ages of the males with the ages of the females.
A record was kept of the number of hours, \(X\), spent by each member at the club in a year. The results were summarised by
$$n = 49 , \quad \Sigma ( x - 200 ) = 245 , \quad \Sigma ( x - 200 ) ^ { 2 } = 9849 .$$
- Calculate the mean and standard deviation of \(X\).