Name:    CP Stat Chap 10 Practice MC Test

Multiple Choice
Identify the choice that best completes the statement or answers the question.

1.

A news organization computes a confidence interval from a sample survey designed to estimate the proportion of  U.S. adults who own smart phones. The interval is 43% to 53%. The margin of error for this confidence interval is
 a) 5% b) 3% c) 6% d) 4%

2.

A news organization computes a confidence interval from a sample survey designed to estimate the proportion of  U.S. adults who own smart phones. The interval is 43% to 53%. The sample proportion used to construct this interval is
 a) 49% b) 48% c) 53% d) 50%

3.

A 95% confidence interval for the mean m of a population is computed from a random sample and found to be 12 ± 4. We may conclude that
 a) 95% of the time, when we estimate m, we will get the interval 8 to 16 b) we can be 95% confident that the mean m is between 8 and 16. c) 95% of all data in this distribution for this variable is between 8 and 16. d) there is a 95% probability that m is between 8 and 16.

4.

A statistics student performs a survey to determine the percentage of seniors at her school who are planning to go to college after graduation. Out of the 186 students she surveys, 136 say they plan to go to college. The sample proportion for this survey is
 a) 0.269 b) 0.789 c) 0.656 d) 0.731

5.

A statistics student performs a survey to determine the percentage of seniors at her school who are planning to go to college after graduation. Out of the 186 students she surveys, 136 say they plan to go to college. The margin of error for a 95% confidence interval for the true proportion of seniors at her school who plan to go to college is closest to
 a) 0.04 b) 0.02 c) 0.06 d) 0.03

6.

The t* for a one-sample mean confidence interval with n = 28 observations and 95% confidence  is
 a) 2.052 b) 2.056 c) 2.048 d) 2.05

7.

If the sample size for a survey is decreased, which of the following would happen?
 a) the margin of error would increase b) the margin of error would stay the same c) the margin of error would decrease d) the margin of error would become negative

8.

I compute a 99% confidence interval for m. Suppose I then compute a 90% confidence interval from the same data. Which of the following statements is true?
 a) The 90% confidence interval would be wider. b) The intervals would have the same width. c) It is not possible to know which interval would be wider. d) The 99% confidence interval would be wider.

9.

A 99% confidence interval for the mean height of of 5th grade girls is found to be (57.5,62.3).  The sample mean used to create this interval is
 a) 58.8 b) 59.3 c) 59.9 d) 58.1

10.

A 99% confidence interval for the mean height of of 5th grade girls is found to be (57.5,62.3).  The margin of error of this interval is
 a) 3.6 b) 3.2 c) 4.8 d) 2.4