Answer these questions. Explain your answers fully.

A company examining its employee retention rates considers the number of complete years a new employee works for a particular division before leaving. The results are shown in the table below: Division A 6 DO DO Division B DO W A 9 Division C 10 9 8 5 7 (i) Perform a one-way analysis of variance at the 5% level to compare the retention rates for the three divisions. [5] (ii) Present the data in a simple diagram and hence comment briefly on the validity of the assumptions required for the analysis of variance. [2] (iii) Concern is expressed over the variability of the results in Division B. It is thought that this might be significantly different from the assumed common underlying variance. (a) Write down an estimate for the underlying common variance for all three divisions. (b) Calculate an unbiased estimate for the variance in Division B based on the data for Division B only. (c) Test at the 5% level whether the variance in Division B is significantly different from your estimate in (iii)(a). [5] [Total 12]The force of interest at time f is given by: 0.01 +0.01f Ost