A sample of 25 is selected from a known population of 100 elements. What is the finite
population correction factor?
A. 8.66
B. 75
C. 0.87
D. Cannot be determined
Data for selected fruits purchased at wholesale prices for 2005 and 2009 are shown
next.
What is the interpretation of the value index?
A. Value rose 9.4%.
B. Value rose 79.1%.
C. Value rose 12.7%.
D. Value rose 12.0%.
A recent study of the relationship between social activity and education for a sample of
corporate executives showed the following results.
What is the value of the chi-square test statistic?
A. 100
B. 83.67
C. 50
D. 4.94
A sampling plan states that if 20 incoming transistors are checked and 2 or less defects
are found, the lot is accepted. If an incoming lot is 10 percent defective, what is the
probability of accepting the lot of transistors?
A. 0
B. 1
C. 0.677
D. 0.333
Refer to the following frequency distribution on days absent during a calendar year by
employees of a manufacturing company:
How many employees were absent six days or more?
A. 8
B. 4
C. 22
D. 31
The mean annual income of certified welders is normally distributed with a mean of
$50,000 and a population standard deviation of $2,000. The ship building association
wishes to find out whether their welders earn more or less than $50,000 annually. The
alternate hypothesis is that the mean is not $50,000. If the level of significance is 0.10,
what is the decision rule?
A. Do not reject the null hypothesis if computed z lies between -1.645 and +1.645;
otherwise, reject it.
B. Do not reject the null hypothesis if computed z is greater than 1.645; otherwise,
reject it.
C. Do not reject the null hypothesis if computed z lies between -1.960 and +1.960;
otherwise, reject it.
D. Reject the null hypothesis if computed z is below -1.960; otherwise, reject it.
Consider a regression model involving more than one independent variable. The test
used to determine if the relationship between the dependent variable and the set of
independent variables is significant is the _______.
A. z-test
B. test
C. chi-square test
D. F-test
Twenty economists were sampled and asked to predict if the national economy would
improve during the next 12 months. Eleven of the economists predicted an increase,
two economists predicted no change, and seven economists predicted a decrease in the
economy. Conduct a hypothesis test at the 0.10 significance level to determine if the
majority of economists predict an increase. The correct analysis would be:
A. a sign test based on the binomial distribution.
B. a sign test based on the standard normal distribution.
C. a chi-square test.
D. a Wilcoxon signed-rank test.
The Intelligence Quotient (IQ) test scores for adults are normally distributed with a
mean of 100 and a standard deviation of 15. What is the probability we could select a
sample of 50 adults and find the mean of this sample is between 95 and 105?
A. 0.0182
B. 0.9818
C. 1.00
D. Very unlikely
In a two-way ANOVA, the sources of variation are _________________.
A. total variation and error variation
B. total variation, treatment variation, and error variation
C. total variation, treatment variation, blocking variation, and error variation
D. treatment variation and blocking variation
What is the test statistic to test the significance of the slope in a regression equation?
A. z-statistic
B. F-statistic
C. t-statistic
D. π-statistic
The employees of Cartwright Manufacturing are awarded efficiency ratings. The
distribution of the ratings approximates a normal distribution. The mean is 400, the
standard deviation is 50. What is the area under the normal curve between 400 and 482?
A. 0.5000
B. 0.4495
C. 0.3413
D. 0.4750
The trend forecast equation is Ŷ = 100 + 120t. The next forecast is for period 11. The
typical seasonal index for period 11 is 1.25. What are the forecast sales for period 11?
A. 1,420
B. 1,775
C. 1,320
D. 1,075
What level of measurement is a person’s “favorite sport”?
A. Ratio
B. Ordinal
C. Interval
D. Nominal
A survey of property owners’ opinions about a street-widening project was taken to
determine if owners’ opinions were related to the distance between their home and the
street. A randomly selected sample of 100 property owners was contacted and the
results are shown next.
What is the expected frequency for people who are undecided about the project and
have property front-footage between 45 and 120 feet?
A. 2.2
B. 3.9
C. 5.0
D. 7.7
For the third quarter, the sales are 1,500 units; the seasonal index for the quarter is 0.90.
What are the deseasonalized sales for the quarter?
A. 0.10
B. 90
C. 1,400
D. 1,667
In a market test of a new chocolate raspberry coffee, a poll of 400 people from Dobbs
Ferry showed 250 preferred the new coffee. In Irvington, 170 out of 350 people
preferred the new coffee. To test the hypothesis that there is no difference in preferences
between the two villages, what is the null hypothesis?
A. H0: π1 < π2
B. H0: π1 > π2
C. H0: π1 = π2
D. H0: π1 ≠π2
A preliminary study of hourly wages paid to unskilled employees in three metropolitan
areas was conducted. Seven employees were included from Area A, 9 from Area B, and
12 from Area C. The test statistic was computed to be 4.91. What can we conclude at
the 0.05 level?
A. The mean hourly wages of unskilled employees of all areas are equal.
B. The mean hourly wages in at least two metropolitan areas are different.
C. More degrees of freedom are needed.
A graphical method used to calculate joint and conditional probabilities is __________.
A. A tree diagram
B. A Venn diagram
C. A histogram
D. Inferential statistics
The tread life of tires mounted on light-duty trucks follows the normal probability
distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles.
Suppose we select a sample of 40 tires and use a simulator to determine the tread life.
What is the standard error of the mean?
A. 632.46
B. 40
C. 4000
D. Cannot be determined.
A random sample of size 15 is selected from a normal population. The population
standard deviation is unknown. Assume the null hypothesis indicates a two-tailed test
and the researcher decided to use the 0.10 significance level. For what values of t will
the null hypothesis not be rejected?
A. To the left of -1.282 or to the right of 1.282
B. To the left of -1.345 or to the right of 1.345
C. Between -1.761 and 1.761
D. To the left of -1.645 or to the right of 1.645
A random sample of 30 executives from companies with assets over $1 million was
selected and asked for their annual income and level of education. The ANOVA
comparing the average income among three levels of education rejected the null
hypothesis. The mean square error (MSE) was 243.7. The following table summarized
the results:
When comparing the mean annual incomes for executives with a high school education
or less and those with an undergraduate degree, the 95% confidence interval shows an
interval of 11.7 to 42.7 for the difference. This result indicates that
__________________.
A. there is no significant difference between the two incomes
B. the interval contains a difference of zero
C. executives with an undergraduate degree earn significantly more than executives
with a high school education or less
D. executives with an undergraduate degree earn significantly less than executives with
a high school education or less
Which of the following is an example of a continuous variable?
A. Tons of concrete to complete a parking garage
B. Number of students in a statistics class
C. Zip codes of shoppers
D. Rankings of baseball teams in a league
A _____________ transformation should be used for a time series that increases by
equal percentages over time.
The paired t test is especially appropriate when the two samples are ________.
A survey of property owners’ opinions about a street-widening project was taken to
determine if owners’ opinions were related to the distance between their home and the
street. A randomly selected sample of 100 property owners was contacted and the
results are shown next.
What is the alternative hypothesis?
A survey of property owners’ opinions about a street-widening project was taken to
determine if owners’ opinions were related to the distance between their home and the
street. A randomly selected sample of 100 property owners was contacted and the
results are shown next.
What is the null hypothesis?
A plastics manufacturer performed a quarterly time series analysis for demands over the
last five years (periods 1 through 20). The analysis resulted in the following trend
equation and seasonal indexes:
= 920.0 + 22.6t
Based on the seasonal indexes, which quarter is expected to have 21% more demand
than predicted by the trend line?
What is the practical value of knowing the value of perfect information?
A company wants to study the effect of an employee’s length of employment on their
number of workdays absent. The results of the regression analysis follow.
What is the least squares equation?
What is the critical value of t for the claim that the difference of two means is less than
zero with α = 0.025 and sample sizes of nine and seven? Assume equal population
standard deviations.
A financial planner wants to compare the yield of income and growth mutual funds.
Fifty thousand dollars is invested in each of a sample of 35 income and 40 growth
funds. The mean increase for a two-year period for the income funds is $900. For the
growth funds, the mean increase is $875. Income funds have a sample standard
deviation of $35; growth funds have a sample standard deviation of $45. Assume that
the population standard deviations are equal. At the 0.05 significance level, is there a
difference in the mean yields of the two funds?
What is the null hypothesis?