Two brands of laptop batteries are compared for their autonomy, which is the time of

operation between two refills.

From each brand, a sample is taken. The results are as follows:

Brand A: average autonomy observed in the sample: ???1? = 155 ??, standard deviation in the

sample: ?1 = 26 ??, sample size: ?1=12

Brand B: ???2? = 136 ??, ?2 = 31 ??, ?2 = 10.

Test the hypothesis at the 5% level of significance that the two brands have equal mean

autonomies against the alternative that their autonomies are different. We may assume that the

two samples are drawn independently from normal distributions with equal variances.

#3) (4 pts) Two brands of laptop batteries are compared for their autonomy, which is the time of operation between two rells. From each brand, a sample is taken. The results are as follows: Brand A: average autonomy observed in the sample: = 155 mn, standard deviation in the sample: 5'1 = 26 mn, sample size: 731:12 Brand B: = 136 mn,52 = 31 mn,n2 = 10. Test the hypothesis at the 5% level of signicance that the two brands have equal mean autonomies against the alternative that their autonomies are different. We may assume that the two samples are drawn independently from normal distributions with equal variances