If there are two unbiased estimators of a population parameter available, the one that
has the smallest variance is said to be:
a biased estimator.
relatively efficient.
consistent.
relatively unbiased
A test is being conducted to test the differences between two population means using
data that are gathered from a matched pairs experiment. If the paired differences are
normal, then the distribution used for testing is the:
normal distribution.
binomial distribution.
Student t-distribution.
F-distribution.
The librarian at the Library of Congress has asked her assistant for an interval estimate
of the mean number of books checked out each day. The assistant took a sample and
found the mean to be 880 books. She provides the librarian with an interval estimate of
between 790 and 970 books checked out per day. An efficient, unbiased point estimate
of the number of books checked out each day at the Library of Congress is:
790
880
90
None of these choices.
Given that X is a binomial random variable with very large n, the binomial probability
P(X ≤ 5) is approximated by the area under a normal curve to the left of
5
−5
5.5
4.5
If the events A and B are independent with P(A) = 0.30 and P(B) = 0.40, then the
probability that both events will occur simultaneously is:
0
0.12
0.70
Not enough information to tell.
If X and Y are any random variables with E(X ) = 5 , E(Y) = 6 , E(XY) = 21 ,
V (X ) = 9 and V (Y) = 10 , then the relationship between X and Y is a:
strong positive relationship
strong negative relationship
weak positive relationship
weak negative relationship
If A and B are independent events with P(A) = 0.60 and P(A | B) = 0.60 , then
P(B) is:
1.20
0.60
0.36
cannot be determined with the information given
How does conducting multiple t-tests compare to conducting a single F-test?
Multiple t-tests increase the chance of a Type I error.
Multiple t-tests decrease the chance of a Type I error.
Multiple t-tests do not affect the chance of a Type I error.
This comparison cannot be made without knowing the number of populations.
A marketing consultant was in the process of studying the perceptions of married
couples concerning their weekly food expenditures. He believed that the husband’s
perception would be higher that the wife’s. To judge his belief, he takes a random
sample of ten married couples and asks each spouse to estimate the family food
expenditure (in dollars) during the previous week. The data are shown below. Can the
consultant conclude at the 5% significance level that the husband’s estimate is higher
than the wife’s estimate? (10%)
The probability that a patient recovers from a rare blood disease is 0.4. (10%)
If 100 people are known to have contracted this disease, what is the probability that
less than 30 survive?
The probability that a patient recovers from a rare blood disease is 0.4. (10%)
If 100 people are known to have contracted this disease, what is the probability that
exactly 35 survive?
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