Two independent samples Z test
Two independent samples have been selected, 92 observations from population 1 and 72 observations from population 2. The sample means have been find outd to be ~x= 6.9 and x2 = 11.4. From previous experience with these populations, it is known that variances are of standard deviation 1= 37 and standard deviation 2| = 31.
(a) Find out standard deviation (x1-x2).
(b) Determine the rejection region for the test of Ho: (mean 1 - mean 2) > 2.43 Use a = 0.04. z > _____________________
(c) find out the test statistic.
z = ______________________
(d) build a 96 percent confidence interval for (/j] -fi2).