1. A university wants to estimate the average amount of money that students spend on books in a semester. It takes a random sampleof 45 students and finds that the average amount of money spent was $282 with a standard deviationof $21. Find a 95% confidence intervalestimate for the true meanamount of money spent on books in a semester.

2. A local public television station, which broadcasts educational programs, is soliciting contributions from its audience during pledge week. The master of ceremonies states that the average contribution of its members is $47. do you think that this average is the mean modeor median? Why?

3. A surveyfound that 30% of pet owners had their pets bathed professionally rather than doing it themselves. If 18 pet owners are randomly selected find the probabilitythat exactly 5 people have their pets professionally bathed.

4. The Statistical Bulletin published by the Metropolitan life insurance company reported 2% of all Americans birth results in twins. If a random sample of 8000 births is taken, find the mean, varianceand standard deviation of the number of births that would result in twins.

5. It was found that 60% of Americans victims of health care fraud are senior citizens. If 10 victims are randomly selected, find the probability that exactly 3 are senior citizens.

6. Find the mean, mode, median, variance and standard deviation of the following data:

35

45

30

35

40

25

7. A survey of 30 adults found that the mean age of a person’s primary vehicle is 5.6 years. Assuming the standard deviation of the population is .8 years, find the 95% confidence interval of the population mean.

8. Find everything to the left of Z= 2.42

9. Find everything to the right of Z= -1.68

10. Find everything in between -1.68 and 2.42

1. A university wants to estimate the average amount of money that students spend on books in a semester. It takes a random sample of 45 students and finds that the average amount of money spent was $282 with a standard deviation of $21. Find a 95% confidence interval estimate for the true mean amount of money spent on books in a semester.

CI = xbar +/- z(s/square root n)

Where xbar is the mean, z is the z value from the desired confidence level (1.96 for 95% confidence level) s is the sample standard deviation and n is the sample size.

CI = 282 +/- 1.96(21/square root 21)

= 282 +/- 6.1358

= 275.86 and 288.14

2. A local public television station, which broadcasts educational programs, is soliciting contributions from its audience during pledge week. The master of ceremonies states that the average contribution of its members is $47. do you think that this average is the mean mode or median? Why?

This would be the mean as mean and average have the same definition for general use to the …

Complete solutions for 10 general statistics problems.