Q-5a. One of the important features of a camera is the battery life as measured by the number of shots ...

Q-5a. One of the important features of a camera is the battery life as measured by the number of shots taken until the battery needs to be recharged. The data at left contain the battery life of 31 subcompact cameras and 15 compact cameras. 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 at the 95% confidence level?

      Subcompact Compact   320 520   520 260   160 400   160 200   300 300   120 150   520 360   440 200   300 260   170 80   150 200   300 260   180 400   100 260   150 200   400    170    180    160    240    320    260    150    320    180    140    220    160    340    200    130