5.2.4 Hypothesis Tests (Proportions) - tests concerning the difference between two proportions


This statlet tests hypotheses about the parameters of two binomial distributions. The tabs are:

Input

Hypothesis test

Power curve


Input

To use this statlet, enter information about your data:

Sample labels - names to be displayed on the output.

Sample sizes - the sizes of the samples.

Sample proportions - the observed sample proportions.

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Hypothesis test

This tab shows the result of a hypothesis test concerning the difference between the proportions:

It shows:

Summary statistics.

A confidence interval for the difference between the proportions.

The result of a hypothesis test run to test a hypothesis about the difference between the proportions.

Use the Options button to specify the hypotheses to be tested. If the P-value is less than the alpha risk which you specify, you should reject the null hypothesis at the corresponding significance level.

Options button

Enter:

Null hypothesis - the value of the difference between the proportions specified by the null hypothesis.

Alt. Hypothesis - select a two-sided test (~=) or a one-sided test.

Alpha - the probability of a Type I error, which is a situation where a true null hypothesis is incorrectly rejected. Typical values for alpha are 10%, 5%, and 1%. The confidence interval is also affected by this setting and uses a confidence level equal to (100-alpha)%.

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Power curve

This tab shows the power curve for the hypothesis test:

The power curve shows the probability of rejecting the null hypothesis as a function of the true difference between the population proportions.

Options button

Same as previous tab.

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