DS 300 Sample Final Exam
Choose the one alternative that best completes the statement or answers the question
1) Since a __________ is not a randomly selected probability sample, there is no way to know how
well it represents the overall population.
A) convenience sample
B) stratified sample
C) simple random sample
D) cluster sample
2) It is desired to estimate the average total compensation of CEOs in the Service industry. Data were
randomly collected from 18 CEOs and the 97% confidence interval was calculated to be ($2,181,260,
$5,836,180). Based on the interval above, do you believe the average total compensation of CEOs in
the Service industry is more than $3,000,000?
A) I am 97% confident that the average compensation is $3,000,000.
B) I cannot conclude that the average exceeds $3,000,000 at the 97% confidence level.
C) Yes, and I am 78% confident of it.
D) Yes, and I am 97% confident of it.
3) A university dean is interested in determining the proportion of students who receive some sort of
financial aid. Rather than examine the records for all students, the dean randomly selects 200
students and finds that 118 of them are receiving financial aid. If the dean wanted to estimate the
proportion of all students receiving financial aid to within 3% with 99% reliability, how many
students would need to be sampled?
4) Suppose a 95% confidence interval for
turns out to be (1,000, 2,100). To make more useful
inferences from the data, it is desired to reduce the width of the confidence interval. Which of the
following will result in a reduced interval width?
A) Decrese the sample size.
B) Decrease the confidence level.
C) Increase the population size.
D) Increase the sample standard deviation.
5) If, as a result of a hypothesis test, we reject the null hypothesis when it is false, then we have
A) a Type II error.
B) a Type I error.
C) an acceptance error.
D) no error.
6) A __________ is a numerical quantity computed from the data of a sample and is used in reaching a
decision on whether or not to reject the null hypothesis.
A) significance level
C) critical value
D) test statistic