Exercises. 1. Explain which of the following is a two tailed test, a left tailed test, or a right tailed test.

1. Explain which of the following is a two tailed test, a left tailed test, or a right tailed test.

a)

b)

c)

Show the rejection and nonrejection regions for each of these cases by drawing a sampling distribution curve for the sample mean, assuming that sample size is large in each case.

2. Consider against .

a) What type of error would you make if the null hypothesis is actually false and you fail to reject it?

b) What type of error would you make if the null hypothesis is actually true and you reject it?

3. For each of the following rejection regions, sketch the sampling distribution for and indicate the location of rejection region.

a) ; b) ; c) ;

d) ; f) or ;

g) or

4. Write the null hypothesis and alternative hypothesis for each of the following examples. Determine if each is a case of a two tailed, a left tailed, or a right tailed test.

a) To test whether or not the mean price of houses in a certain city is greater than $ 45 000.

b) To test if the mean number of hours spent working per week by students who hold jobs is different from 18 hours.

c) To test whether the mean life of a particular brand of auto batteries is less than 28 days.

d) To test if the mean amount of time taken by all workers to do a certain job is more than 45 minutes.

f) To test the mean age of all managers of companies is different from 40 years.

g) To test the mean time for an airline passenger to obtain his or her luggage, once luggage starts coming out the conveyer belt, is less than 180 seconds.

1.2. Tests of the mean of a normal distribution:

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