Construct a 90% confidence interval for u, – U, with the sample statistics for mean cholesterol content of a hamburger from two fast food chains and confidence interval construction formula below. Assume the populations are approximately normal with unequal variances. X, = 111 mg, s, =3.93 mg, n, =20 X2 = 105 mg, s2 = 2.02 mg, nɔ = 12 Stats s s Confidence interval when variances are not equal d.f. is the smaller of n, - 1 or n2 - 1 Enter the endpoints of the interval.

Sony would like to test the hypothesis that the average age of a PlayStation user is different from the average age of an Xbox user. A random sample of 32 PlayStation users had an average age of 33.7 years while a random sample of 36 Xbox users had an average age of 35.6 years. Assume that the population standard deviation for the age of PlayStation and Xbox users is 3.7 and 3.5 years, respectively. Also assume population variances are equal. Sony would like to set alpha= 0.05. The 95% confidence interval for the difference in population means is

A large p-value indicates that the data is consistent with the alternative hypothesis.   True or false?

The valve pressure was tested on 250 engines and the mean pressure was 5.9 lbs/square inch. Assume the variance is known to be 0.36. If the valve was designed to produce a mean pressure of 5.8 lbs/square inch, is there sufficient evidence at the 0.02 level that the valve performs about the specifications?