Question

11. A political polling organization conducted a survey by selecting 100 random samples, each consisting of 500 registered voters. The registered voters in each sample were asked whether they planned to vote for the Republican or Democratic candidate in the next presidential election. For each of the 100 samples, the polling organization created a 99 percent confidence interval for the proportion of all registered voters who planned to vote for the Republican candidate.

Which of the following statements is the best interpretation of the 99 percent confidence level?

(A) We would expect about 99 of the 100 confidence intervals to contain the sample proportion of the registered voters who plan to vote for the Republican candidate.
(B) We would expect about 99 of the 100 confidence intervals to contain the proportion of all registered voters who plan to vote for the Republican candidate.
(C) We would expect the margin of error to be 0.01 because the polling organization constructed 99 percent confidence intervals.
(D) We would expect the margin of error to be less than 0.01 because the polling organization constructed 100 different 99 percent confidence intervals.
(E) We would expect only 1 of the 100 confidence intervals to reveal that the Democratic candidate is favored.


12. A pharmaceutical company claims that side effects will be experienced by fewer than 20% of the patients who use medication X. A clinical trial with a random sample of 400 patients was conducted in which half of the patients were randomly assigned to take medication X and the other half received a placebo. Of those that received medication X they find 68 who experienced side effects.
Assuming all conditions for inference were met, which of the following is a 90 percent confidence interval for the proportion of patients that will experience side effects while taking medication X?

(A) (0.1391, 0.2009)
(B) (0.2744, 0.4057)
(C) (0.2849, 0.3951)
(D) (0.6257, 0.7343)
(E) (0.6416, 0.7184)

13. Household income in the United States is strongly skewed to the right. The current presidential administration claims that the mean household income is greater than it has ever been in the past. An independent contractor will obtain a random sample of 100 households in the United States and will calculate the mean household income. Which of the following statements is true?
(A) The sampling distribution of the sample mean household income is approximately normal because the sample size of 100 is greater than 30.
(B) The distribution of household income for the sample is approximately normal because the sample size of 100 is greater than 30.
(C) The sampling distribution of the sample mean household income is strongly skewed to the right because the population standard deviation is unknown.
(D) The distribution of household income is strongly skewed to the left because the population sample size of 100 is greater than 30.
(E) The sampling distribution of the sample mean household income is strongly skewed to the right because the population distribution is strongly skewed to the right.

Answer 1

11. A political polling organization conducted a survey by selecting 100 random samples, each consisting of 500 registered voters. The registered voters in each sample were.......

(D) We would expect the margin of error to be less than 0.01 because the polling organization constructed 100 different 99 percent confidence intervals

12. A pharmaceutical company claims that side effects will be experienced by fewer than 20% of the patients who use medication X. A clinical trial with a random sample of 400 patients was conducted in..........

(E) (0.6416, 0.7184)

13. Household income in the United States is strongly skewed to the right. The current presidential administration claims that the mean household income is greater than it has ever been in the past. An independent contractor will..................

(C) The sampling distribution of the sample mean household income is strongly skewed to the right because the population standard deviation is unknown.

Step-by-step explanation:

Answer 2

Answer:11. (B) We would expect 99 of the 100 confidence intervals to contain the proportion of all registered voters who plan to vote for the Republican candidate.

12. (C) (0.2849, 0.3951)

13. (A) The sampling distribution of the sample mean household income is approximately normal because the sample size of 100 is greater than 30.

Step-by-step explanation: