1.1. A selection of data from the large data set relating to the daily mean cloud cover, measured in oktas, in Heathrow for the first 10 days in May 1987 is given below.

7         4         5         2         7         4          2         0          3          5

Using your knowledge of the large data set, explain why a value of 10 oktas would be impossible.

1.2. Find:

(i) the value of the median of the data,

(ii) the interquartile range of the data.