Hypothesis TestingMajor Steps

1. State the hypotheses.

Be sure to state both the null hypothesis and the alternative hypothesis, and identify which is the claim.

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H0

Null Hypothesis◦ Either states that there is no difference

between a parameter and a specific value or that there is no difference between parameters

◦H0: m ≤ 100 H0: p = 60% and H0: s 1 are examples of null hypotheses.

Statistical Hypotheses

Alternative Hypothesis◦ Either states that there is a difference between a

parameter and a specific value or that there is a difference between parameters

◦H1: m > 100 H1: p 60% and H1: s < 1 are examples of alternative hypotheses.

Statistical Hypotheses

2. Design the study.

This step includes selecting the correct statistical test, choosing a level of significance, and formulating a plan to carry out the study.

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A t-test, a z-test, or a Chi-square test ─ that is the question!

2. Design the study.

The plan should include information such as the definition of the population, the way the sample will be selected, and the methods that will be used to gather the data.

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3. Conduct the study and collect the data.

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since the sample means vary about the population mean, even if the null hypothesis is true, the sample mean will not, in most cases, be exactly equal to the population mean. So, . . .

For instance…

How close is close enough?

Is the difference “significant” or likely due to “chance”?

Just where does the researcher draw the line?

4. Evaluate the data.

The data should be tabulated in this step, and the statistical test should be conducted. Find the critical value(s). Compute the test value. Finally, decide whether to reject or not reject the null hypothesis.

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H0 True H0 False

Reject H0 Error

Type I Correct decision

Do not reject H0

Correct decision

Error Type II

A Type I error occurs if one rejects the null hypothesis when it is true.

A Type II error occurs if one does not reject a null hypothesis when it is false.

Decision Issues

5. Summarize the results. Write a specific conclusion involving the claim (which

may or may not be the null hypothesis). Refer to our text for the types of conclusions which may be made.

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