This calculator is used to compare the proportions from two independent groups to determine if they are significantly different from one another.

Step 1

Select desired confidence level:

90 95 99  %

Step 2

Group 1 Information
Enter the sample size and either the frequency or percent from the first group; the other value will auto-calculate.

Group 1

sample size

Step 3

Group 2 Information
Enter the sample size and either the frequency or percent from the second group; the other value will auto-calculate.

Group 2

sample size

RESULTS

1-Tail   

  2-Tail

Actual Confidence Level:

%

Are means significantly different at the selected confidence level?

What the results mean

When you interview two independent samples, there is some likelihood (confidence level) that the means obtained from the two groups are significantly different. If the t-value obtained from this test is greater than the t distribution value for a given confidence level, the observed means are significantly different.

More information

Step 1: Confidence Level

The value chosen in Step 1 determines the confidence level of your results. It tells you the likelihood that the difference in proportions is NOT due to random chance. For most marketing research studies, a confidence level of 95% is used.

Confidence level is related to the level of significance (α ). A 95% Confidence level corresponds to α = .05. If the Level of significance (α) = .05, that means that there is one chance in twenty that the two proportions are not really different.

Step 2: Enter Group 1 Information

Enter the base size (# answering the question). Then enter either the frequency or the percentage of respondents answering the question in the manner to be tested. Note, you only need to enter one of these two values, the second value will automatically calculate off of the other value.

Step 3: Enter Group 2 Information

Repeat Step 2 using the base size (# answering the question) and the frequency or percentage of respondents answering in the manner to be tested from the second group of respondents.

Click the calculator button to obtain the results of the test.

Assumptions

It is assumed that your sample represents a random sample of the relevant population and that each group to be tested is independent of the other.

It is not necessary for the two groups to have the same number of respondents.

This calculator calculates both one-tail and two-tailed tests. If you are testing the null hypothesis that the two proportions are equal, use the two-tailed test result. A one-tailed tests is used if you are trying to determine if one proportion is greater (or lower) than another.