Find the area under the standard normal curve between  and .

Find the standardized test statistic estimate, , to test the hypothesis that . Use α = 0.01. The sample statistics listed below are from independent samples.Sample statistics: ,  , and  ,

Given the linear correlation coefficient , determine the coefficient of determination, 

Find the test statistic, , to test the hypothesis that

Determine the standardized test statistic, z, to test the claim about the population proportion  given and

Many people think that a national lobby’s successful fight against gun control legislation is reflecting the will of a minority of Americans. A random sample of 4000 citizens yielded 2250 who are in favor of gun control legislation. Estimate the true proportion of all Americans who are in favor of gun control legislation using a 90% confidence interval. Express the answer in the form

In 2010, the mean expenditure for auto insurance in a certain state was $806. An insurance salesperson in this state believes that the mean expenditure for auto insurance is less today. She obtains a simple random sample of 32 auto insurance policies and determines the mean expenditure to be $781 with a standard deviation of $39.13.  (a) What are the null and alternative hypotheses? (b)  If the calculated P-value = 0.0005, is there enough evidence to support the claim that the mean expenditure for auto insurance is less than the 2010 amount at the α = 0.05 level of significance?

Determine the critical value

A least-square regression line is given by

A severe drought affected several western states for 3 years. A Christmas tree farmer is worried about the drought’s effect on the size of his trees. To decide whether the growth of the trees has been retarded, the farmer decides to take a sample of the heights of 25 trees. Typically trees of this age have a mean height of 65 inches with a standard deviation of 9 inches. Assuming the distribution is bell shaped, where do you expect middle 95% of the tree heights to fall?