A sample of ten 40-W light bulbs was taken from each of three manufacturing plants. The bulbs were burned until failure. The number of hours that each remained lit is listed in the following table.

(a) Test the hypothesis that the median lives of bulbs produced at the three plants are all the same. Use the 0.05 level of significance.
(b) Are the mean lives of bulbs produced at the three plants all the same? Use the analysis of variance with α = 0.05.
(c) Change the observation €œ2246€ in the third column to €œ1500€ and redo part (a). How does this change affect the hypothesis test?
(d) Change the observation €œ2246€ in the third column to €œ1500€ and redo part (b). How does this change affect the hypothesis test?

Transcribed Image Text:

Plan Plant 2 Plant 3 905 1109 571 1018 1155 1346 905 835 292 886 1152 825 958 1036 676 1056 926 541 904 1029 818 90 1070 959 2246 1006 996104 856 1040