Question

A consumer advocate researches the length of life between two brands of refrigerators, Brand A and Brand B. He collects data (measured in years) on the longevity of 40 refrigerators for Brand A and repeats the sampling for Brand B. These data are measured in years. (You may find it useful to reference the appropriate table: z table or t table) Brand A Brand B Brand A Brand B 24 24 25 23 24 19 19 16 13 19 21 18 21 13 15 17 18 21 12 21 20 25 13 14 23 25 16 18 23 21 19 24 15 24 21 14 20 24 12 19 21 17 25 13 16 20 12 25 12 20 12 18 16 12 20 20 21 21 13 15 17 15 17 21 13 15 Assume that #1 is the mean longevity for Brand A and 2 is the mean longevity for Brand B

Answer 1

Answer Date: 09/08/2019 b-1) The z-test statistics is, 2) By using Excel software, find z-test statistics with the help of following steps: 1) Import the data. Select z test: Two Sample for Means from Data Analysis in Data menu. Select Variable 1 Range and Variable 2 Range. 4) Select Variable 1 Variance (known) and Variable 2 Variance (known). Give Hypothesized Mean Difference. Select Labels and give Alpha. Choose Output Range from Output options. Click Ok. 5)

z-Test: Two Sample for Means Brand A 17.975 4.8 40 Brand B 19.1 5.5 Mean Known Variance Observations Hypothesized Mean Difference 40 P(Z<=z) one-tail z Critical one-tail P(Z<=z) two-tail z Critical two-tail -2.21699 0.013312 1.644854 0.026624 1.959964 From the Excel output, the z-test statistics is - 2.22.