#1 Construct the indicated confidence interval for the population mean using the t-distribution. Assume the population is normally distributed.

c=0.90, x=13.6, s=2.0, n=5

(Round to one decimal place as needed.)

#2 Construct the indicated confidence interval for the population mean using the t-distribution. Assume the population is normally distributed.

c=0.90, x=12.3, s=0.74, n=17

(Round to one decimal place as needed.)

#3 In a random sample of 18 people, the mean commute time to work was 32.6 minutes and the standard deviation was 7.1 minutes. Assume the population is normally distributed and use a t-distribution to construct a 80% confidence interval for the population mean .

What is the margin of error of ? Interpret the results.

The confidence interval for the population mean is

(Round to one decimal place as needed.)

#4 The state test scores for randomly selected high school seniors are shown on the right. Complete parts (a) through (c) below.

Assume the population is normally distributed. 1424 1226 986 693 721 832 728 743 547 626 1450 946

(a) Find the sample mean.

(b) Find the sample standard deviation.

(c) Construct a 99% confidence interval for the population mean .

(Round to one decimal place as needed.)

#5 Use the standard normal distribution or the t-distribution to construct a 90% confidence interval for the population mean. Justify your decision. If neither distribution can be used, explain why. Interpret the results.In a random sample of 13 mortgage institutions, the mean interest rate was 3.61% and the standard deviation was 0.49%. Assume the interest rates are normally distributed.

The 99% confidence interval is?

#6 Let p be the population proportion for the following condition. Find the point estimates for p and q. In a survey of 1034 adults from country A, 113 said that they were not confident that the food they eat in country A is safe.

The point estimate for p, p, is

The point estimate for q, q, is

(Round to three decimal places as needed.)

#7 Let p be the population proportion for the following condition. Find the point estimates for p and q. Of 971 children surveyed, 126 plan to join the armed forces in the future.

#8 In a survey of 2544 adults, 1480 say they have started paying bills online in the last year. Construct a 99% confidence interval for the population proportion. Interpret the results.

#9 A researcher wishes to estimate, with 99% confidence, the population proportion of adults who think Congress is doing a good or excellent job. Her estimate must be accurate within 3%

of the true proportion.

(a) No preliminary estimate is available. Find the minimum sample size needed. (Round up to the nearest whole number as needed.)

(b) Find the minimum sample size needed, using a prior study that found that 28% of the respondents said they think Congress is doing a good or excellent job.

(c) Compare the results from parts (a) and (b).

#10 In a survey of 4079 adults, 700 oppose allowing transgender students to use the bathrooms of the opposite biological sex.

Construct a 99% confidence interval for the population proportion. Interpret the results.

#11 A researcher wishes to estimate, with 90% confidence, the population proportion of adults who support labeling legislation for genetically modified organisms (GMOs). Her estimate must be accurate within 3% of the true proportion.

(a) No preliminary estimate is available. Find the minimum sample size needed.

(b) Find the minimum sample size needed, using a prior study that found that 71% of the respondents said they support labeling legislation for GMOs.

(c) Compare the results from parts (a) and (b).