skewed to the left.
skewed to the right.
not skewed.
normally distributed.
Manuel Banales, Marketing Director of Plano Power Plants, Inc.’s
Electrical Division, is leading a study to assess the relative importance of
product features. Two items on a survey questionnaire distributed to 100 of
Plano’s customers asked them to rate the importance of “ease of
maintenance” and “efficiency of operation” on a scale of 1 to 10 (with 1
meaning “not important” and 10 meaning “highly important”). His staff
assembled the following statistics on these two items.
The Ease of Maintenance distribution has more relative dispersion.
the Ease of Maintenance distribution has less dispersion.
the Efficiency of Operation distribution is skewed to the left.
the Efficiency of Operation distribution has less dispersion.
The staffs of the accounting and the quality control departments rated
their respective supervisor’s leadership style as either (1) authoritarian or
(2) participatory. Their responses are tabulated in the following table.
Which of the following statements is NOT true?
Authoritarian and Participatory are mutually exclusive.
Accounting and Quality Control are complements.
Accounting and Participatory are dependent.
Accounting and Quality Control are collectively exhaustive.
In order to determine whether or not a particular medication was effective
in curing the common cold, one group of patients was given the medication,
while another group received sugar pills. The results of the study are
shown below.
10.08
54.02
1.96
1.645
The following graph indicates a __________
2×4 completely randomized design with interaction.
2 × 4 factorial design with interaction.
4 ×2 factorial design with interaction.
4 ×2 completely randomized design with no interaction.
A production process produces 2% defective parts. A sample of 5 parts from
the production is selected. What is the probability that the sample contains
exactly two defective parts? Use the binomial probability function and
show your computations to answer this question. ___(3)___
The time it takes a mechanic to change the oil in a car is exponentially
distributed with a mean of 5 minutes. What is the probability that it will
take a mechanic less than 6 minutes to change the oil?
Purchasing magazine reported the results of a survey in which buyers
were asked a series of questions with regard to Internet usage. One
question asked was how they would use the Internet if security and other
issues could be resolved. Eighty percent said they would use it for pricing
information. A researcher randomly samples 20 buyers and asks them how
they would use the Internet if security and other issues could be resolved.
a. what is the probability that exactly 10 of these buyers would use it for
pricing information? ___(5)___
b. Suppose 100 buyers and asks them how they would use the Internet if
security and other issues could be resolved. What is the probability that
fewer than 80 of these buyers would use it for pricing information? ___(6)___
c. Suppose 100 buyers and asks them how they would use the Internet if
security and other issues could be resolved. What is the probability that
the sample proportion is fewer than 76%? ___(7)___
A math department needs to estimate the average time it takes Statistics I
students to finish a computer project to within 2 hours at 98% reliability. It
is estimated that the standard deviation of the times is 14 hours. How
large a sample should be taken to get the desired interval?
20
265
17
115
A test of hypothesis was performed to determine if the true proportion of
college students who preferred a particular brand of soda differs from .50.
The ASP printout is supplied below. Note: All data refer to the proportion
of students who preferred the brand of soda.
HYPOTHESIS MEAN X = x
SAMPLE PROPORTION OF X = .407186
SAMPLE SIZE OF X = 167
HYPOTHESIZED VALUE (x) = .3
X = drink_(soda = 1)
SAMPLE PROPORTION X – x = –.092814
Z = –2.39884 P-VALUE = .0164 P-VALUE/2 = .0082
SD. ERROR = .0386912
Based on the interval above, where would the 99% confidence interval for
the true proportion be located?
completely above .5
completely below .5
cannot tell from this test of hypothesis printout.
with .5 contained in the interval.
An insurance company states that their claim office is able to process all
death claims within 4 working days. Recently there have been several
complaints that it took longer than 4 days to process a claim. Top
management wants to make sure that the situation is status quo and sets
up a statistical test with a null hypothesis that the average time for
processing a claim is 4 days, and an alternative hypothesis that the
average time for processing a claim is greater than 4 days, and an
alternative hypothesis that the average time for processing a claim is
greater than 4 days. After completing the statistical test. It is concluded
that the average exceeds 4 days. However, it is eventually learned that the
mean process time is really 4 days. What type of error occurred in the
statistical test?
No error occurred in the statistical sense.
Type I error.
Type III error.
Type II error.
About 44% of the total variation in the sample of y-values can be
explained by the linear relationship between appraised value and
number of rooms.
We expect 95% of the observed appraised values to lie on the least
squares line.
We expect to predict the appraised value of an East Meadow house to
within about $58,000 of its true value.
We expect to predict the appraised value of an East Meadow house to
within about $29,000 of its true value.
Company D only.
Companies B and C only.
Companies B and D only.
Company C only.
There is insufficient evidence (at α = .01 ) to conclude that the
first-order model is statistically useful for predicting GPA.
Over 99% of the variation in GPAs can be explained by the model.
There is sufficient evidence (at α = .01 ) to conclude that the first-order
model is statistically useful for predicting GPA.
Model 1
Model 2
Model 3
Unknown it depends on which model is the best predictor.
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