Two Sample Z-Test


The following results are for independent random samples taken from two Populations. Consider the following hypothesis test:

Ho: m1 - m2 0
Ha: m1 - m2 > 0

Sample 1      Sample 2

n1 = 40         n2 = 50

x1 = 25.2       x2 = 22.8

s1 = 5.2         s2 = 6.0

Using alpha = .05, test the hypothesis. What is your conclusion?

For this problem we will use a Z-test and we will reject Ho if p < .05

Start from the "TESTS" menu.

Press Arrow right to "TESTS" and

Arrow down to "3 : 2-SampZTest..."

Press (see screen below)

Recall for large n, s can be substituted for s.

Choose "Stats" and press Enter. Next, match the settings on your calculator to those on the above screen. Be sure you choose the alternative test " > 2 "

Arrow down to "Calculate" and press ( this screen will appear )



From the screen the p-value = .02 which is < .05 therefore we reject Ho