1.A researcher conducted a survey of graduating college students. 350 college students were randomly selected to answer the survey. One of the survey questions asked, "What are your plans after graduation?" 214 students said they were planning to find a job, 83 students said they were planning to attend graduate school, and 53 students did not reply to the question.

What is the point estimate for the proportion of all college students who plan to find a job after graduation?

Group of answer choices

a)214

b) 83

c) 0.61

d) 0.24

Question 2

Based on survey results, the proportion of U.S. adults who own at least one Apple product (iphone, ipad, macbook, etc) is 0.42. This point estimate would be unbiased and most accurate if the survey were based on which of the following?

Group of answer choices

a) A random sample of 1,000 U.S. adults

b) A random sample of 1,800 U.S. adults

c) A random sample of 2,500 U.S. college students

d) An internet survey posted on TechGuru.com with 3,100 responses

Question 3

Suppose we take repeated random samples of 50 college students from the same population and determine a 95% confidence interval for the mean GPA from each sample. Which of the following statements is true regarding the confidence intervals? Check all that apply.

Group of answer choices

a) The intervals are centered around the population mean GPA.

b)The intervals are centered around the sample mean GPA.

c)95% of the intervals will contain the sample mean in the long run.

d)95% of the intervals will contain the population mean in the long run.

Question 4

A random sample of 30 students taking statistics at a community college found the student's mean GPA to be 3.25. A 95% confidence interval for the mean GPA of all students taking statistics at this college was determined to be (3.07, 3.43). What is the margin of error for this confidence interval?

Group of answer choices

a) 095

b) 0.36

c) 0.18

d) 3.25

Question 5

Assuming data come from a random sample, under which of the following conditions should we not calculate a confidence interval for a population mean?

Group of answer choices

a) Population is normally distributed and sample size is 50 individuals.

b) Population is normally distributed and sample size is 20 individuals.

c) Population distribution is unknown and sample size is 20 individuals.

d)Population distribution is unknown and sample size is 50 individuals.

Question 6

For the following scenario, is the variable is categorical or quantitative?

A poll of students at your college is asked whether or not they plan to attend graduate school after graduation.

Group of answer choices

a) Categorical

b) Quantitative

Question 7

We say that a point estimator is unbiased if which of the following is true?

Group of answer choices

a) Its sampling distribution is centered exactly at the parameter it estimates.

b)The standard deviation of its sampling distribution decreases as the sample size increases.

c)Its value is always equal to the parameter it estimates.

d)Its sampling distribution is normal.

Question 8

A study was conducted to estimate , the mean commute distance that all employed U.S. adults travel to work. Suppose a random sample of 49 employed U.S. adults gives a mean commute distance of 22 miles and that from prior studies, the population standard deviation is assumed to be = 8.4 miles.

Based on this information, what would be the point estimate for ?

Group of answer choices

a) 49

b) 22

c) 1.2

d) 8.4

Question 9

A study was conducted to estimate , the mean commute distance that all employed U.S. adults travel to work. Suppose a random sample of 49 employed U.S. adults gives a mean commute distance of 22 miles and that from prior studies, the population standard deviation is assumed to be = 8.4 miles.

We are 95% confident that the mean commute distance to work of all employed U.S. adults falls between which of the following intervals?

Group of answer choices

a) 5.2 to 38.8

b) 20.8 to 23.2

c) 19.6 to 24.4

d)18.4 to 25.6

Question 10

A human resource manager for a large company takes a random sample of 60 employees from the company database. Based on the sample she calculates a 95% confidence interval for the mean time of employment for all employees to be 8.7 to 15.2 years.

Which of the following will provide a more informative (i.e., narrower) confidence interval than the 95% confidence interval? Check all that apply.

Group of answer choices

a)Using a 90% confidence level (instead of 95%)

b)Using a 99% confidence level (instead of 95%)

c)Using a sample size of 40 employees (instead of 60)

d)Using a sample size of 90 employees (instead of 60)

Question 11

A study was conducted to estimate , the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard deviation is assumed to be = 3.6 hours.

How large a sample of U.S. adults is needed in order to estimate with a 95% confidence interval of length 1.2 hours?

Group of answer choices

a)6

b)12

c)20

d)36

e)144

Question 12

A researcher would like to estimate p, the proportion of U.S. adults who support recognizing civil unions between gay or lesbian couples.

If the researcher would like to be 95% sure that the obtained sample proportion would be within 1.5% of p (the proportion in the entire population of U.S. adults), what sample size should be used?

Group of answer choices

a) 17,778

b)4,445

c)1,112

d)67

e)45