What is a normal distribution with a mean of 0 and a standard deviation of 1 called?
A. Frequency distribution
B. Z-score
C. Standard normal distribution
D. Binomial probability distribution
Which of the following is NOT a characteristic of a binomial probability distribution?
A. Each outcome is mutually exclusive.
B. Each trial is independent.
C. The probability of success remains constant from trial to trial.
D. The number of trials is limited to two.
A nonparametric test requires that the data can be:
A. ranked.
B. summed.
C. graphed.
D. transformed.
Students were sampled in order to determine their support for the legalization of
gambling in their community. A sample of 150 students were asked whether or not they
supported legalization of gambling, and the following results were obtained.
The number of degrees of freedom associated with this scenario is _____.
A. 149
B. 2
C. 150
D. 3
A hypothesis regarding the weight of newborn infants at a community hospital is that
the mean is 6.6 pounds. A sample of seven infants is randomly selected and their
weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the
sample mean?
A. 6.6
B. 7.6
C. 1.177
D. 2.447
Which condition must be met to conduct a test for the difference in two sample means
using a z-statistic?
A. The data must be at least of nominal scale.
B. The populations must be normal.
C. The two population standard deviations must be known.
D. The samples are dependent.
A marketing firm is studying consumer preferences for winter fashions in four different
months. From a population of women 18 to 21 years of age, a random sample of 100
women was selected in January. Another random sample of 100 women was selected in
March. Another random sample of 100 women was selected in June. Another random
sample of 100 women was selected in September. What is the sample size?
A. 4
B. 100
C. 400
D. 1
The mean of all possible sample means is equal to ____________.
A. The population variance
B.
C. The sample variance
D. The population mean
Each person who applies for an assembly job at Robert’s Electronics is given a
mechanical aptitude test. One part of the test involves assembling a plug-in unit based
on numbered instructions. A sample of the length of time it took 42 persons to assemble
the unit was organized into the following frequency distribution.
What is the standard deviation (in minutes)?
A. 3.89
B. 6.01
C. 8.78
D. 17.00
A student was studying the political party preferences of a university’s student
population. The survey instrument asked students to identify themselves as a Democrat
or a Republican. This question is flawed because:
A. Students generally don’t know their political preferences.
B. The categories are generally mutually exclusive.
C. The categories are not exhaustive.
D. Political preference is a continuous variable.
The national sales manager for “I colored this” (ICT) T-shirts provides all salespersons
with the following opportunity loss table showing the potential lost profit for each
purchase decision or act from one to four dozen T-shirts. The probability of demand for
each state of nature is also shown.
How many dozen T-shirts should you purchase based on minimizing the expected
opportunity loss?
A. 1
B. 2
C. 3
D. 4
Production of passenger cars in Japan increased from 3.94 million in 1999 to 6.74
million in 2009. What is the geometric mean annual percent increase?
A. 4.0
B. 1.9
C. 5.5
D. 16.6
E. 47.3
The interquartile range is graphically presented in a ___________.
A. Dot plot
B. Stem-and-leaf display
C. Box plot
D. Contingency table
A hypothesis regarding the weight of newborn infants at a community hospital is that
the mean is 6.6 pounds. A sample of seven infants is randomly selected and their
weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the
decision for a statistical significant change in average weights at birth at the 5% level of
significance?
A. Fail to reject the null hypothesis.
B. Reject the null hypothesis and conclude the mean is higher than 6.6 lb.
C. Reject the null hypothesis and conclude the mean is lower than 6.6 lb.
D. Cannot calculate because the population standard deviation is unknown.
An accelerated life test on a large number of type-D alkaline batteries revealed that the
mean life for a particular use before they failed is 19.0 hours. The distribution of the
lives approximated a normal distribution. The standard deviation of the distribution was
1.2 hours. About 95.44% of the batteries failed between what two values?
A. 8.9 and 18.9
B. 12.2 and 14.2
C. 14.1 and 22.1
D. 16.6 and 21.4
A company is researching the effectiveness of a new website design to decrease the
time to access a website. Five website users were randomly selected, and their times (in
seconds) to access the website with the old and new designs were recorded. To compare
the times, they computed (new website design time – old website design time). The
results follow.
What is the value of the test statistic?
A. 2.256
B. 1.895
C. 3.747
D. 2.447
The manager of Paul’s fruit and vegetable store is considering the purchase of a new
seedless watermelon from a wholesale distributor. Since this seedless watermelon costs
$4, will sell for $7, and is highly perishable, he only expects to sell between six and
nine of them. What is the payoff value for the purchase of eight watermelons when the
demand is for eight or more watermelons?
A. 17
B. 21
C. 24
D. 10
A logarithmic trend equation should be used when the time series trend is
__________________.
A. changing in equal amounts
B. increasing by equal percentages
C. increasing in equal amounts
D. increasing or decreasing by equal percentages
The best example of a null hypothesis for testing an individual regression coefficient is
__________.
A. H0: β1 = β2 = β3 = β4 = 0
B. H0: 1 = 2 = 3 = 4 = 0
C. H0: β1 = 0
D. H0: β1 ≠0
When testing H0: Median equals $12.40 and the alternate hypothesis: Median does not
equal $12.40, what is the critical value of z at the 10% level of significance?
A. 1.96
B. 1.65
C. 2.33
D. 0.10
Refer to the following breakdown of responses to a survey of “Are you concerned about
being tracked while connected to the Internet?”
What type of chart should be used to describe the frequency table?
A. A pie chart
B. A bar chart
C. A histogram
D. A frequency polygon
What type of variable is the number of auto accidents reported in a given month?
A. Interval
B. Ratio
C. Continuous
D. Discrete
Using the following regression analysis:
What is the residual sum of squares?
To construct a binomial distribution, we need to know the ___________ and the
probability of a success.
A manufacturer claims that less than 1% of all its products do not meet the minimum
government standards. A survey of 500 products revealed that 10 did not meet the
standard. If the z-statistic is -2.58 and the level of significance is 0.02, your decision
would be __________.
If the size of a sample equals the size of the population, the sampling error is ________.
Coastal Carolina University recently surveyed a sample of students to determine how
far they lived from campus. The results are shown below. Compute the standard
deviation.
In an acceptance sampling plan, the incoming lot is ___________ if the number of
defective items in the sample is less than or equal to the acceptance number.
In a relative frequency distribution, the sum of the relative class frequencies is
_____________________.