Question: As a test of worthiness of a new software package, an experiment was designed where 10 particular financial applications projects are used by the new software package as well as by the current leading package. The following table shows the processing times (in seconds) by using those two software packages.

a) Test the hypothesis that the mean processing time of the new software package equals the mean processing time of the current one. Use ? = 0.05 and assume equal variances.

b) Assuming the variances of each sample are equal, construct a 95% confidence interval on the difference in the mean processing times.

c) Test whether the variances of two software packages are equal. Use ? = 0.05.

d) Does the assumption of normality seem appropriate for these data?