How can I develop a C.I. based on this information? Is drawing a C.I. sufficient enough?

Twelve randomlj.F selected mature citrus trees of one variety have a mean height of 14.2 ft with a standard deviation of 1.2ft1 and 15 randomljgvr selected mature citrus trees of another variety have a mean height of 13.1 ft with a standard deviation of 1.5ft. Assume the height of the trees is well modelled by a normal distribution. {a} Assuming equal variances, construct a 95% CI for the dj'erence between the true average heights of the two kinds of citrus trees. [b} Assuming lmequal variances, construct a 98% CI for the ratio of the variances of the two populations sampled