An important feature of digital cameras is battery life, the number of shots that can be taken before the battery needs to be recharged. The file contains battery life information for 29 subcompact cameras and 16 compact cameras. (Data extracted from "Digital Cameras," Consumer Reports, July 2009, pp. 28-29.)
a. Is there evidence of a difference in the variability of the battery life between the two types of digital cameras? (Use .05)
b. Determine the p-value in (a) and interpret its meaning.
c. What assumption about the population distribution of the two types of cameras is necessary in (a)? Is the assumption valid for these data?
d. Based on the results of (a), which t test defined in Section 10.1 should you use to compare the mean battery life of the two types of cameras?
|
Subcompact
|
Compact
|
|
300
|
400
|
|
310
|
450
|
|
290
|
450
|
|
280
|
260
|
|
250
|
350
|
|
200
|
240
|
|
330
|
330
|
|
240
|
220
|
|
280
|
230
|
|
240
|
260
|
|
200
|
280
|
|
220
|
400
|
|
280
|
500
|
|
210
|
200
|
|
260
|
150
|
|
220
|
130
|
|
240
|
|
|
210
|
|
|
205
|
|
|
290
|
|
|
160
|
|
|
280
|
|
|
200
|
|
|
140
|
|
|
230
|
|
|
220
|
|
|
200
|
|
|
170
|
|
|
150
|
|