Inference aplet 11-9
Results The results are:
Two-Sample Z-Test
Menu name Z-Test: μ1–μ2
On the basis of two samples, each from a separate 
population, this test measures the strength of the evidence 
for a selected hypothesis against the null hypothesis. The 
null hypothesis is that the mean of the two populations are 
equal (H
0
: μ1= μ2).
You select one of the following alternative hypotheses 
against which to test the null hypothesis:
Inputs The inputs are:
Result Description
Test Z Z-test statistic.
Prob Probability associated with the 
Z-Test statistic.
Critical Z Boundary values of Z 
associated with the α level that 
you supplied.
Critical 
Boundary values of   required 
by the α value that you 
supplied.
x
x
H
1
:μ
1
μ
2
<
H
1
:μ
1
μ
2
>
H
1
:μ
1
μ
2
≠
Field name Definition 
Sample 1 mean.
Sample 2 mean.
n1 Sample 1 size.
n2 Sample 2 size.
σ1 Population 1 standard 
deviation.
1
2
HP 39gs English.book  Page 9  Wednesday, December 7, 2005  11:24 PM