# Project #4902 - Statistics

1. Freshmen’s GPA – First semester GPAs for a random selection of freshmen at a large university are shown below. Estimate the true mean GPA of the freshmen class with 99% confidence. Assume o~=0.62

*Also state an interpretation for the confidence interval

1.9  3.22.02.92.73.3

2.83.03.82.72.01.9

2.52.72.83.23.03.8

3.12.73.53.83.92.7

2.02.81.94.02.22.8

2.12.43.03.42.92.1

2. Chocolate Chips per Cookie- It is desired to estimate the mean number of chocolate chips per cookie for a large national brand. How many cookies would have to be sampled to estimate the true mean number of chips per cookie within 2 cups with 98% confidence? Assume that o~= 10.1 chips

3. Students per Teacher in U.S. Public Schools- The national average for the number of students per teacher for all U.S. public schools is 15.9. A random sample of 12 school districts from a moderately populated area showed that the mean number of students per teacher was 19.2 with a variance of 4.41. Estimate the true mean number of students per teacher with 95% confidence. How does your estimate compare with the national average?

*Also state an interpretation for the confidence interval

4. Belief in Haunted Places – A random sample of 205 college students was asked if they believed that places could be haunted, and 65 of them responded yes. Estimate the true proportion of college students who believe in the possibility of haunted place with 99% confidence. According to Time magazine, 37% of Americans believe that places can be haunted.

*Also state an interpretation for the confidence interval

5. Perform each of the following steps:

a.State the hypotheses and identify the claim.

b. Find the critical values

c. Compute the test value.

d. Make the decision.

e. Summarize the results.

Credit Card Debt- It has been reported that the average credit card debt for college seniors is \$3262. The student senate at a large university feels that their seniors have a debt much less than this, so it conducts a study of 50 randomly selected seniors and finds that the average debt is \$2995, and the population standard deviation is \$1100. With a= 0.05, is the student senate correct?

6. Perform each of the following steps:

a.State the hypotheses and identify the claim.

b. Find the critical values

c. Compute the test value.

d. Make the decision.

e. Summarize the results.

Public School Teacher Salaries- The average salary for public school teachers for a specific year was reported to be \$39,385. A random sample of 50 public school teacher in a particular state had a mean of \$41,680, and the population standard deviation is \$5975. Is there sufficient evidence at the a= 0.05 level to conclude that the mean salary differs form \$39,385?

7. Park Acreage – A state executive claims that the average number of acres in western Pennsylvania state parks is less then 2000 acres. A random sample of five parks is selected, and the number of acres is shown. At a= 0.01, is there enough evidence to support the claim?

95911874936249541

8. *Use traditional method of hypothesis testing

Home Ownership- A recent survey found that 68.6% of the population own their homes. In a random sample of 150 heads of households, 92 responded that they owned their home. At the a=0.01 level of significance , does that suggest a difference from the national proportion?

 Subject Mathematics Due By (Pacific Time) 04/25/2013 09:00 pm
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