c. The rail company in part b decides to employ additional maintenance staff on seven of its lines in an effort to test if this will improve the service. The inspector again collects data on how many trains were cancelled, shown in Table 4 Table 4: Number of trains cancelled before and after employment of additional maintenance staff , Lines 1-7. Number of trains cancelled Before After Show how the inspector should use this data to test if employing additional maintenance staff has led to a reduction in the number of trains cancelled. Do you think they should recommend additional maintenance staff be employed on all lines? [5 marks] d. Calculate the 95% condence interval for the variance, based on a sample estimate of s=25 and a sample size of 100. Remember to show your method. [5 marks]