Question

A manufacturer claims that the calling range (in feet) of its 900-MHz cordless telephone is greater than that of its leading competitor. A sample of 21 phones from the manufacturer had a mean range of 1140 feet with a standard deviation of 43 feet. A sample of 11 similar phones from its competitor had a mean range of 1110 feet with a standard deviation of 38 feet. Do the results support the manufacturer's claim? Let μ1 be the true mean range of the manufacturer's cordless telephone and μ2 be the true mean range of the competitor's cordless telephone. Use a significance level of α=0.1 for the test. Assume that the population variances are equal and that the two populations are normally distributed.

Answer 1