An important feature of digital cameras is battery life-the number of shots that can be taken before the batter) needs to be recharged. The file Cameras contains the battery life of 11 subcompact cameras and 7 compact cameras.
a. Assuming that the population variances from both types of digital cameras are equal, is there evidence of a difference in the mean battery life between the two types of digital cameras (a = 0.05)?
b. Determine the p-value in (a) and interpret its meaning.
c. Assuming that the population variances from both types of digital cameras are equal, construct and interpret a 95% confidence interval estimate of the difference between the population mean battery life of the two types of digital cameras.