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Z-test for Proportions-Dependent Groups

This calculator is used to compare the proportions from two overlapping groups (i.e. groups that contain the same people) to determine if they are significantly different from one another. It allows you to enter the information for as many as 10 groups at a time. The calculator will then perform the Z-test for every possible combination of groups.

This test assumes you have a large population.

How To Interpret The Results

For example, suppose you carried out a paired preference test amongst 200 respondents and you are interested in whether there is a difference between the observed results for likelihood to purchase between the trial product (Group 1) and standard product (Group 2), at the 95% confidence level.

Input

Output

 Sample Size Group 1 Group 2
Group 1 Group 2 Group 1
Observed Sample Proportion Group 2

‘NO’ indicates that there is not a significant difference between the two observed proportions, i.e. there is no significant difference in the proportion of respondents who are likely to purchase the trial or standard products .

Calculator

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Confidence Level

The degree of confidence in whether or not the true figure for the population lies within the confidence interval for the survey.

For example, a 95% confidence level indicates there is a 1 in 20 (5%) chance that the true population result falls outside the confidence interval range.

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Sample Size

The number of respondents who answered the question.

Group 12345678910
Observed Sample Proportion ?

Observed Sample Proportion (Enter as a %)

The percentage of respondents who gave the response you are interested in.

Results

Use the calculator above to calculate your results.