A transport company wants to compare the fuel efficiencies of the two types of lorry it operates. It obtains data from samples of the two types of lorry, with the following results:
|
Type
|
Average mpg
|
Std devn
|
Sample Size
|
|
A
|
31.0
|
7.6
|
33
|
|
B
|
32.2
|
5.8
|
40
|
Test the hypothesis that there is no difference in fuel efficiency, using the 99% confidence level.