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Hypothesis formation

#1
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:
U=
Xbar=
N=
S=
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.

#2
Why does a null and alternative hypothesis have to be mutually exclusive?

#3
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.

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