13.19 It is suspected that the environmental temperature at which batteries are activated affects their life.

Thirty homogeneous batteries were tested, six at each of five temperatures, and the data are shown below

(activated life in seconds). Analyze and interpret the data. (From C. R. Hicks, Fundamental Concepts in Design of Experiments, Holt, Rinehart and Winston, New York, 1973.)

Temperature (◦C)

0 25 50 75 100 55 60 70 72 65 55 61 72 72 66 57 60 72 72 60 54 60 68 70 64 54 60 77 68 65 56 60 77 69 65