The manufacturer for cpu cooling device claims to keep the cpu at (or below) an average temperature of 65C throughout normal use. A research team is skeptical as well as wishes to give evidence that the average temperature is greater than 65C.
(a) Determine the null and alternative hypotheses appropriate for the research team? Define any parameter(s) used.
(b) A cooling device will be used on each of a sample of 12 cpus. How high must the average cpu temperature be in this sample in order to reject the manufacturer's claim with a significance level of .05? Past research has shown that the standard deviation for cpu temperatures with this device is 5C. You may also assume that cpu temperatures are approximately normally distributed.
(c) After an hour of use, it turns out that the average cpu temperature is 67.8C for the 12 devices. Calculate the test statistic and p-value for this test.
(d) At a .05 significance level, what is the researcher's conclusion about the manufacturer's claim?