This test is used for large samples to test the hypothesis:
H_{0}: the proportion is the same in both populations
H_{1}: the proportions are different/the proportion is greater for process 1 than process 2
The value of the Z statistic is calculated from:
where:
p_{1} and p2: the proportions in each sample
X_{1} and X_{2}: the number possessing the characteristic in each sample
n_{1} and n_{2}: the sample size
The pvalue can be obtained from Excel using the function:
onetail test: = 1  NORMSDIST(Z_{0})
twotail test: = (1  NORMSDIST(Z_{0}))/2
Alternatively the critical values can be found in the ttables.
Hypothesis Test for Proportions 

For large samples, refer to the tests "Comparing Proportions" and "Proportions Against a Specified Value". For small sample sizes refer to ChiSquare tests.
Proportion Against a Specified Value 

This test is used for large samples to test the hypothesis:
H_{0}: the proportion is the same in both populations
H_{1}: the proportion is [different to/greater than/less than] the specified value
The value of the Z statistic is calculated from:
the proportion in the sample
the specified value of the proportion
n the sample size
The pvalue can be obtained from Excel using the function:
onetail test: = 1  NORMSDIST(Z_{0})
twotail test: = (1  NORMSDIST(Z_{0}))/2
Alternatively the critical values can be found in the ttables.
