A company that supports two different types of computer networks is interested in comparing the mean down time for the two types. A random sample of 12 networks from the first type and another random sample of 18 networks from the second type are selected and the down time in hours (over a one-year period) is recorded for every network. The results are given in the table below:
Type1 Type 2
Sample mean 83.5 75.4
Sample standard deviation 29.2 22.3
a) Is theresufficient evidence to conclude that the two samples are coming from two populations with different variances? Use ? = 0.01.
b) Do the data provide sufficient evidence to conclude that the mean down time fornetwork type 1is greater than that of the network type 2? Use ?=0.01. State your assumptions.