Question

1. What is a sampling distribution?

A) A distribution of respondent frequencies for all variables in a survey.

B) A visual method for displaying statistics.

C) A theoretical distribution of all possible sample values for the statistic in which we are interested.

D) None of the above.

2. True or false, the Central Limit Theorem for sample means says that if larger and larger samples are drawn from the population, the distribution of the sample means will approximate a normal distribution?

A) True

B) False

3. What is captured by the standard error of the mean? (choose all that apply)

A) The CLT and the sampling distribution.

B) The probability that the interval around the point estimate contains the actual population mean.

C) The standard deviation of a sampling distribution average.

D) A normal distribution of samples and the probability of an equal standard deviation.

4. Estimation is a process that

A) Uses random sampling to define statistics or a range of statistics.

B) Uses a sample statistic to approximate a population parameter or a range that may contain the population parameter.

C) Is unrelated to inferential statistics.

D) Is only used for descriptive statistics.

5. Is the t distribution symmetrical or skewed?

A) Symmetrical

B) Skewed

6. Which of the following is not needed in calculating a confidence interval for a population mean?

A) A point estimate of the population mean

B) An estimate of the population variance

C) A confidence level

D) All of the above are necessary.

E) None of the above are necessary.

7. According to a Field Poll, 79% of California adults (actual results are 400 out of 506 surveyed) feel that “education and our schools” is one of the top issues facing California. We wish to construct a 90% confidence interval for the true proportion of California adults who feel that education and schools is one of the top issues facing California. Based on this information, a point estimate for the true population proportion is:

A) 400

B) 0.79

C) 0.90

D) 1.27

8.If a confidence level is increased from 90% to 99%, how would the confidence interval change?

A) It would stay the same

B) It would become wider

C) It would become narrower

9.Based on your answer to Question #8, why would this happen? Choose all that apply

A) The calculation for the interval would remain unchanged, so the interval would stay the same.

B) The Z score multiplier is greater, so the interval becomes wider.

C) More observations need to be included to increase confidence of the inclusion of the true population parameter, so the interval becomes wider.

D) The Z score multiplier is greater, so the interval becomes narrower.

E) The precision of the inclusion of the true population parameter increases, so the interval becomes narrower.

Answer 1