A lab orders 100 rats a week for each of the 52 weeks in the year for
experiments that the lab conducts. Suppose the mean cost of rats used in
lab experiments turned out to be $13.00 per week. Interpret this value.
Most of the weeks resulted in rat costs of $13.00.
The rat cost that occurs more often than any other is $13.00.
The expected or average cost for all weekly rat purchases is $13.00.
The median cost for the distribution of rat costs is $13.00.
The local police department must write, on average, 5 tickets a day to keep
department revenues at budgeted levels. Suppose the number of tickets
written per day follows a Poisson distribution with a mean of 6.5 tickets
per day. Interpret the value of the mean.
Half of the days have less than 6.5 tickets written and half of the days
have more than 6.5 tickets written.
If we sampled all days, the arithmetic average or expected number of
tickets written would be 6.5 tickets per day.
The number of tickets that is written most often is 6.5 tickets per day.
The mean has no interpretation since 0.5 ticket can never be written.
A company has 125 personal computers. The probability that any one of
them will require repair on a given day is 0.15. Which of the following is
one of the properties required so that the binomial distribution can be used
to compute the probability that no more than 2 computers will require
repair on a given day?
The number of personal computers the company owns on a given day is
fixed.
The probability that two or more computers that will require repair in a
given day approaches zero.
The number of computers that will require repair in the morning is
independent of the number of computers that will require repair in the
afternoon.
The probability that a computer that will require repair in the morning
is the same as that in the afternoon.
Sampling distributions describe the distribution of
parameters.
statistics.
both parameters and statistics.
neither parameters nor statistics.
The owner of a fish market has an assistant who has determined that the
weights of catfish are normally distributed, with mean of 3.2 pounds and
standard deviation of 0.8 pound. If a sample of 16 fish is taken, what would
the standard error of the mean weight equal?
0.200
0.050
0.800
0.003
a t distribution with 15 degrees of freedom.
a standard normal distribution.
approximately normal with a mean of $50.50.
a t distribution with 14 degrees of freedom.
Both sampled populations are normally distributed.
Both samples are random and independent.
Neither A nor B is necessary.
Both A and B are necessary.
reject the alternative hypothesis.
reject the null hypothesis.
do not reject the null hypothesis.
It cannot be determined from the information given.
The degrees of freedom for the F test in a one-way ANOVA are
(c − n) and (n −1) .
(n − c) and (c −1) .
(n −1) and (c − n) .
(c −1) and (n − c) .
Reject the null hypothesis because the p-value is larger than the level of
significance.
Do not reject the null hypothesis because the p-value is larger than the
level of significance.
Do not reject the null hypothesis because the p-value is smaller than
the level of significance.
Reject the null hypothesis because the p-value is smaller than the level
of significance.
Referring to the above information, which of the following is the correct
null hypothesis to determine whether there is a significant relationship
between percentage of students passing the proficiency test and the entire
set of explanatory variables?
H0 : β0 = β1 = β2 = β3 = 0
H0 : β1 = β2 = β3 ≠ 0
H0 : β0 = β1 = β2 = β3 ≠ 0
H0 : β1 = β2 = β3 = 0
A multiple-choice test has 30 questions. There are 4 choices for each
question. A student who has not studied for the test decides to answer all
questions randomly. What type of probability distribution can be used to
figure out his chance of getting at least 20 questions right?
hypergometric distribution.
Poisson distribution.
binomial distribution.
none of the above.
A catalog company that receives the majority of its orders by telephone
conducted a study to determine how long customers were willing to wait on
hold before ordering a product. The length of time was found to be a
random variable best approximated by an exponential distribution with a
mean equal to 2.8 minutes. What proportion of callers is put on hold longer
than 2.8 minutes?
0.50
0.632121
0.367879
0.60810
In the game Wheel of Fortune, which of the following distributions can best
be used to compute the probability of winning the special vacation package
in a single spin?
binomial distribution.
normal distribution.
exponential distribution.
uniform distribution.
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?
n =1,784
n =1,435
n =1,503
n = 1,844
At α = 0.10 , there is sufficient evidence to conclude that the average
number of tissues used during a cold is not 60 tissues.
At α = 0.05 , there is not sufficient evidence to conclude that the
average number of tissues used during a cold is 60 tissues.
At α = 0.05 , there is not sufficient evidence to conclude that the
average number of tissues used during a cold is not 60 tissues.
At α = 0.05 , there is sufficient evidence to conclude that the average
number of tissues used during a cold is 60 tissues.
It is believed that the average number of hours spent studying per day
(HOURS) during undergraduate education should have a positive linear
relationship with the starting salary (SALARY, measured in thousands of
dollars per month) after graduation. Given below is the Excel output from
regressing starting salary on number of hours spent studying per day for a
sample of 51 students.
NOTE: Some of the numbers in the output are purposely erased.
5.944E-18.
(5.944E-18)/2.
(2.051E-05)/2.
2.051E-05.
A student claims that he can correctly identify whether a person is a business
major or an agriculture major by the way the person dresses. Suppose in
actuality that if someone is a business major, he can correctly identify that
person as a business major 87% of the time. When a person is an agriculture
major, the student will incorrectly identify that person as a business major 16%
of the time. Presented with one person and asked to identify the major of this
person (who is either a business or agriculture major), he considers this to be a
hypothesis test with the null hypothesis being that the person is a business
major and the alternative that the person is an agriculture major.
Referring to the above information, what would be a Type I error?
Saying that the person is an agriculture major when in fact the person
is a business major.
Saying that the person is a business major when in fact the person is an
agriculture major.
Saying that the person is a business major when in fact the person is a
business major.
Saying that the person is an agriculture major when in fact the person
is an agriculture major.
A debate team of 4 members for a high school will be chosen randomly
from a potential group of 15 students. Ten of the 15 students have no prior
competition experience while the others have some degree of experience.
What is the probability that none of the members chosen for the team have
any competition experience?
There are two houses with almost identical characteristics available for
investment in two different neighborhoods with drastically different
demographic composition. The anticipated gain in value when the house
are sold in 10 years has the following probability distribution:
what is the standard deviation of the value gain for the house in
neighborhood B?
There are two houses with almost identical characteristics available for
investment in two different neighborhoods with drastically different
demographic composition. The anticipated gain in value when the house
are sold in 10 years has the following probability distribution:
if your investment preference is to minimize the amount of risk that
you have to take and do not care at all about the expected return, will
you choose a portfolio that will consist of 10%, 30%, 50,% 70%, or 90%
of your money on the house in neighborhood A and remaining on the
house in neighborhood B?
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