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Hypothesis formation

Use this word example to answer the following questions for question #1. "Joe's repair shop claims that the average repair time is equal to or less then 60 minutes. You wish to test that hypothesis, and take a sample of 64 repair bill, finding the sample mean to be 65 minutes, with a standard deviation of 2 minutes. Using an Alpha of 0.05, you wish to test to see if the average repair time is greater than 60 minutes."

Please note that Joe makes a claim, that is the hypothesis, but you wish to test the alternative which is that the time is greater than 60 minutes. This is a key concept in understanding hypothesis testing.

DQ1-a. List the values for:
Alpha =
Is this a two or one tail test, explain

#1-b. Show the Ho and HA hypothesis statements in symbols. Start with the Ho and Ha as shown and finish them:

Ho: u=< 60 minutes
Ha: u > 60 minutes

Did you get it?

Complete #1, then complete one more example.

Why does a null and alternative hypothesis have to be mutually exclusive?

Why do alphas differ among industries? In your industry what alpha do you think would be appropriate? Common alphas are .01, .05. .10

Solution Preview

U = 60 minutes
Xbar = 65 minutes
N = 64 receipts
S= 2 minutes
Alpha = 0.05

It is a two tailed test because the number of sample is more than 30. According to some sources 30 is 39, but I teach at the 30 level because that is a social science choice. Business often uses the 39.

1 B. A landscape designer claims to use ...

Solution Summary

Answers to four questions based on hypothesis formation and research testing parts.