The table shows the salaries (£'000) of the employees of a company.

Salary (£'000) Number of Employees 20 and less than 30 35 30 and less than 40 75 40 and less than 50 96 50 and less than 60 42 60 and less than 70 52

a) Estimate the modal salary from the histogramdrawn for question 1 in Supplementary exercise2.

b) Estimatethe median from the cumulative frequency diagram drawn the same question.

c) Estimate the quartile values and socalculate the interquartile range of the salaries.

d) From the frequency data above calculate themean salary and the standard deviation for thesalaries of the whole company.