The stability of measurements on a manufactured product is important in maintaining product quality. A manufacturer of lithium batteries, such as the ones used for digital cameras, suspected that one of the production lines was producing batteries with a wide variation in length of life. To test this theory, he randomly selected n = 50 batteries from the suspect line and n = 50 from a line that was judged to be "in control." He then measured the length of time (in hours) until depletion to 0.85V with a 5-Ohm load for both samples. The sample means and variances for the two samples were as follows:

a. Do the data provide sufficient evidence to indicate that batteries produced by the "suspect line" have a larger variance in length of life than those produced by the line that is assumed to be in control? Test using α = .05.
b. Find the approximate p-value for the test and interpret its value.
c. Construct a 90% confidence interval for the variance ratio.

Transcribed Image Text:

Suspect Line e in Contrl" 不 = 940 = .25 9.25 S2-.12