N345 Statistics Exam Study Guide
(4 pts) A choral conductor has 1670 singers in her choir, some of them are professional
singers. The conductor wants to estimate what percentage of singers are professional,
but can't ask all 1670, so she instead asks 652 singers in front and finds 25 who are
professionals.
(a) Identify the parameter
A. 25
B. range of values in which 95% values fall
C. percentage of entire singers who are professional
D. None of the above.
(b) Identify the population
A. 25/1670
B. entire singers
C. percentage of entire singers who are professional
D. None of the above.
(c) What specific type of bias does this scenario demonstrate?
A. Convenience Sampling
B. It is representative of the population.
C. Voluntary response sampling
D. None of the above.
(d) Identify the sample.
A. 25/1670
B. 652
C. singers who were asked
D. None of the above. - ANSWER C
B
, A
C
(a) A news release for a diet product company reports: There's good news for the 65
million Americans currently on a diet. Its study showed that people who lose weight can
keep it off. The sample was 20 graduates of the company's program who endorse it in
commercials. The results of the sample are probably
A. unbiased, but they could be more accurate. A larger sample size should be used.
B. biased, overstating the effectiveness of the diet.
C. biased, understating the effectiveness of the diet.
D. None of the above. - ANSWER B
A sample of 30 dentists from Seattle is taken to estimate the median income of all
Seattle residents.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE?
A simple random sample of men over age 18 is taken to estimate the mean weight of all
adult males.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE?
A simple random sample of voters is taken in order to determine the chances of a
certain candidate winning an election.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE?
Using a sample of 40 patients from a local hospital, researchers measured cholesterol
level in an attempt to estimate the mean cholesterol level of U.S. citizens.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE? - ANSWER B
(4 pts) A choral conductor has 1670 singers in her choir, some of them are professional
singers. The conductor wants to estimate what percentage of singers are professional,
but can't ask all 1670, so she instead asks 652 singers in front and finds 25 who are
professionals.
(a) Identify the parameter
A. 25
B. range of values in which 95% values fall
C. percentage of entire singers who are professional
D. None of the above.
(b) Identify the population
A. 25/1670
B. entire singers
C. percentage of entire singers who are professional
D. None of the above.
(c) What specific type of bias does this scenario demonstrate?
A. Convenience Sampling
B. It is representative of the population.
C. Voluntary response sampling
D. None of the above.
(d) Identify the sample.
A. 25/1670
B. 652
C. singers who were asked
D. None of the above. - ANSWER C
B
, A
C
(a) A news release for a diet product company reports: There's good news for the 65
million Americans currently on a diet. Its study showed that people who lose weight can
keep it off. The sample was 20 graduates of the company's program who endorse it in
commercials. The results of the sample are probably
A. unbiased, but they could be more accurate. A larger sample size should be used.
B. biased, overstating the effectiveness of the diet.
C. biased, understating the effectiveness of the diet.
D. None of the above. - ANSWER B
A sample of 30 dentists from Seattle is taken to estimate the median income of all
Seattle residents.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE?
A simple random sample of men over age 18 is taken to estimate the mean weight of all
adult males.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE?
A simple random sample of voters is taken in order to determine the chances of a
certain candidate winning an election.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE?
Using a sample of 40 patients from a local hospital, researchers measured cholesterol
level in an attempt to estimate the mean cholesterol level of U.S. citizens.
Is this study
A. REPRESENTATIVE?
B. NON-REPRESENTATIVE? - ANSWER B
