1- Explain the meaning of a point estimate and an interval estimate.

a- A point estimate is a population parameter used in calculations while an interval estimate is an interval that is constructed around the point estimate, and it is stated that this interval is likely to contain the corresponding population parameter.

b-The value of a sample statistic used to estimate the standard deviation is an interval estimate, and a point estimate is the value of a sample statistic used to estimate the mean.

c-The value of a sample statistic used to estimate a population parameter is called a point estimate. In interval estimation, an interval is constructed around the point estimate, and it is stated that this interval is likely to contain the corresponding population parameter.

d-The value of a sample statistic used to estimate a population parameter is called an interval estimate. A point estimate is an interval that is constructed around the interval estimate, and it is stated that this interval is likely to contain the corresponding population parameter.

e-The value of a sample statistic used to estimate the mean is an interval estimate, and a point estimate is the value of a sample statistic used to estimate the standard deviation.

2- The standard deviation for a population is=15.3. A sample of23 observations selected from this population gave a mean equal to137.55. The population is known to have a normal distribution. Round your answers to two decimal places.

a.Make a99% confidence interval for.

b.Construct a95% confidence interval for.

c.Determine a90%confidence interval for.

d.Does the width of the confidence intervals constructed in partsathroughcdecrease as the confidence level decreases?

3- The standard deviation for a population is=7.36. A random sample selected from this population gave a mean equal to47.41.Constructa95%

confidence interval for assumingn=100. Round your answers to two decimal places.

4-A city planner wants to estimate the average monthly residential water usage in the city. He selected a random sample of41households from the city, which gave the mean water usage to be3408.80 gallons over a one-month period. Based on earlier data, the population standard deviation of the monthly residential water usage in this city is387.40 gallons. Make a95% confidence interval for the average monthly residential water usage for all households in this city. Round your answers to two decimal places.

5- Find the value oft for thet distribution for the following. Area in the right tail=0.05 anddf=15. Round your answer to 3 decimal places.

6-Find to 3 decimal places the value oft for thet distribution for the following. Area in the left tail=0.005 andn=30.

7- Almost all employees working for financial companies in New York City receive large bonuses at the end of the year. A sample of62 employees selected from financial companies in New York City showed that they received an average bonus of$51,000 last year with a standard deviation of$23,000. Construct a90% confidence interval for the average bonus that all employees working for financial companies in New York City received last year. Round your answers to cents.

8- The high price of medicines is a source of major expense for those seniors in the United States who have to pay for these medicines themselves. A random sample of1400 seniors who pay for their medicines showed that they spent an average of$4500 last year on medicines with a standard deviation of$700. Make a98% confidence interval for the corresponding population mean.

9- A random sample ofn=16 mid-sized cars tested for fuel consumption gave a mean ofx=24.63 miles per gallon with a standard deviation ofs=2.72

miles per gallon. Assuming that the miles per gallon given by all mid-sized cars have a normal distribution, find a99% confidence interval for the population mean,. Round your answers to two decimal places.

10- Check if the sample size is large enough to use the normal distribution to make a confidence interval forp for the following case. n=60 andp^=0.08

11- Determine the most conservative sample size for the estimation of the population proportion for the following. E=0.026, confidence level=95%

Round your answer up to the nearest whole number.

12- According to a Pew Research Center nationwide telephone survey of adults conducted March 15 to April 24, 2011,69% of college graduates said that their college education gave them maturity (Time, May 30, 2011). Suppose that this survey includedn=1465 college graduates.

a.What is the point estimate of the corresponding population proportion?

b.Construct a98% confidence interval for the proportion of all college graduates who will say that their college education gave them maturity. What is the margin of error for this estimate?

13-A researcher wanted to know the percentage of judges who are in favor of the death penalty. He took a random sample of15

judges and asked them whether or not they favor the death penalty. The responses of these judges are given here.

YesNoYesYesNoNoNoYesNoNoYesYesYesNoYes

a.What is the point estimate of the population proportion? Round your answer to three decimal places.

b.Construct a95% confidence interval for the percentage of all judges who are in favor of the death penalty. Round your answers for the confidence interval to three decimal places, and your answers for the percentage confidence interval to one decimal places.

14-A survey of20 randomly selected adult men showed that the mean time they spend per week watching sports on television is9.93 hours with a standard deviation of1.41 hours. Assuming that the time spent per week watching sports on television by all adult men is (approximately) normally distributed, construct a90% confidence interval for the population mean,. Round your answers to two decimal places.