True or False: Suppose = 50 and = 10 for a population. In a sample where n = 100 is
randomly taken, 95% of all possible sample means will fall between 48.04 and 51.96.
TABLE 9-5
A bank tests the null hypothesis that the mean age of the bank’s mortgage holders is less
than or equal to 45 years, versus an alternative that the mean age is greater than 45
years. They take a sample and calculate a p-value of 0.0202.
True or False: Referring to Table 9-5, the null hypothesis would be rejected at a
significance level of = 0.01.
True or False: Apple Computer, Inc. collected information on the age of their
customers. Suppose the youngest customer was 12 and the oldest was 72. To study the
distribution of the age among its customers, it is best to use a pie chart.
True or False: The percentage polygon is formed by having the lower boundary of each
class represent the data in that class and then connecting the sequence of lower
boundaries at their respective class percentages.
TABLE 2-17
The following table presents total retail sales in millions of dollars for the leading
apparel companies over a two-year period.
True or False: Referring to Table 2-17, in general, retail sales for the apparel industry
have seen a modest growth between Year 1 and Year 2.
Referring to Table 14-5, the observed value of the F-statistic is given on the printout as
25.432. What are the degrees of freedom for this F-statistic?
TABLE 14-5
A microeconomist wants to determine how corporate sales are influenced by capital and
wage spending by companies. She proceeds to randomly select 26 large corporations
and record information in millions of dollars. The Microsoft Excel output below shows
results of this multiple regression.
A) 25 for the numerator, 2 for the denominator
B) 2 for the numerator, 23 for the denominator
C) 23 for the numerator, 25 for the denominator
D) 2 for the numerator, 25 for the denominator
TABLE 12-13
Recent studies have found that American children are more obese than in the past. The
amount of time children spent watching television has received much of the blame. A
survey of 100 ten-year-olds revealed the following with regards to weights and average
number of hours a day spent watching television. We are interested in testing whether
the mean number of hours spent watching TV and weights are independent at 1% level
of significance.
Referring to Table 12-13, the degrees of freedom of the test statistic are
A) 1.
B) 2.
C) 4.
D) 9.
True or False: The Analysis of Means (ANOM) is more appropriate if you want to
identify the group(s) that has(have) a higher or lower mean than the overall mean while
the One-Way Analysis of Variance (One-way ANOVA) is more appropriate when you
just want to see if the means of all the different groups are the same.
TABLE 1-2
A Wall Street Journal poll asked 2,150 adults in the United States a series of questions
to find out their view on the U.S. economy.
Referring to Table 1-2, the possible responses to the question “How would you rate the
condition of the U.S. economy with 1 = excellent, 2 = good, 3 = decent, 4 = poor, 5 =
terrible?” are values from a
A) discrete numerical variable.
B) continuous numerical variable.
C) categorical variable.
D) table of random numbers.
An investor wanted to forecast the price of a certain stock. He collected the mean daily
price for the stock over the past 10 years. Which of the following would be the most
appropriate analysis to perform?
A) The Marascuilo Procedure
B) The Tukey-Kramer Procedure
C) Least-squares forecasting with monthly or quarterly data
D) Autoregressive modeling
TABLE 4-4
Suppose that patrons of a restaurant were asked whether they preferred water or
whether they preferred soda. 70% said that they preferred water. 60% of the patrons
were male. 80% of the males preferred water.
Referring to Table 4-4, suppose a randomly selected patron prefers soda. Then the
probability that the patron is a male is ________.
A contractor wants to forecast the number of contracts in future quarters, using
quarterly data on a number of contracts over the last 10 years. Which of the following
would be the most appropriate analysis to perform?
A) Autoregressive modeling
B) One-way ANOVA
C) Least-squares forecasting with monthly or quarterly data
D) Two-way ANOVA
TABLE 18-5
A manufacturer of computer disks took samples of 240 disks on 15 consecutive days.
The number of disks with bad sectors was determined for each of these samples. The
results are in the table that follows.
Referring to Table 18-5, construct a p control chart for these data.
TABLE 3-12
Given below are the rating and performance scores of 15 laptop computers.
Referring to Table 3-12, for a laptop computer that has a high rating, you will expect its
performance score to
A) be about the same as its rating.
B) be low.
C) be high.
D) have no relationship with its rating.
TABLE 12-13
Recent studies have found that American children are more obese than in the past. The
amount of time children spent watching television has received much of the blame. A
survey of 100 ten-year-olds revealed the following with regards to weights and average
number of hours a day spent watching television. We are interested in testing whether
the mean number of hours spent watching TV and weights are independent at 1% level
of significance.
Referring to Table 12-13, which of the following statements is correct?
A) We cannot reject the null for any level of significance greater than 0.005.
B) We can reject the null for any level of significance greater than 0.005.
C) We cannot reject the null for any level of significance smaller than 0.005.
D) We can reject the null for any level of significance smaller than 0.005.
Referring to Table 14-4, the observed value of the F-statistic is missing from the
printout. What are the degrees of freedom for this F-statistic?
A) 2 for the numerator, 47 for the denominator
B) 2 for the numerator, 49 for the denominator
C) 49 for the numerator, 47 for the denominator
D) 47 for the numerator, 49 for the denominator
TABLE 11-2
A realtor wants to compare the mean sales-to-appraisal ratios of residential properties
sold in four neighborhoods (A, B, C, and D). Four properties are randomly selected
from each neighborhood and the ratios recorded for each, as shown below.
Interpret the results of the analysis summarized in the following table:
Referring to Table 11-2, the critical value of Levene’s test for homogeneity of variances
at a 5% level of significance is
A) 0.64.
B) 2.48.
C) 3.29.
D) 3.49.
On the average, 1.8 customers per minute arrive at any one of the checkout counters of
a grocery store. What type of probability distribution can be used to find out the
probability that there will be no customer arriving at a checkout counter?
A) Binomial distribution
B) Poisson distribution
C) Hypergeometric distribution
D) None of the above.
TABLE 11-3
As part of an evaluation program, a sporting goods retailer wanted to compare the
downhill coasting speeds of 4 brands of bicycles. She took 3 of each brand and
determined their maximum downhill speeds. The results are presented in miles per hour
in the table below.
Referring to Table 11-3, construct the ANOVA table from the sample data.
TABLE 18-10
Below is the number of defective items from a production line over twenty consecutive
morning shifts.
Referring to Table 18-10, a c chart is to be constructed for the number of defective
items. The upper control limits is ________.
TABLE 9-12
A drug company is considering marketing a new local anesthetic. The effective time of
the anesthetic the drug company is currently producing has a normal distribution with a
mean of 7.4 minutes with a standard deviation of 1.2 minutes. The chemistry of the new
anesthetic is such that the effective time should be normally distributed with the same
standard deviation. The company will market the new local anesthetic as being better if
there is evidence that the population mean effective time is greater than the 7.4 minutes
of the current local anesthetic.
Referring to Table 9-12, if you select a sample of 25 new local anesthetics and are
willing to have a level of significance of 0.1, the probability of a Type I error is
________ if the population mean effective time is 8 minutes.
TABLE 17-12
The marketing manager for a nationally franchised lawn service company would like to
study the characteristics that differentiate home owners who do and do not have a lawn
service. A random sample of 30 home owners located in a suburban area near a large
city was selected; 15 did not have a lawn service (code 0) and 15 had a lawn service
(code 1). Additional information available concerning these 30 home owners includes
family income (Income, in thousands of dollars), lawn size (Lawn Size, in thousands of
square feet), attitude toward outdoor recreational activities (Attitude 0 = unfavorable, 1
= favorable), number of teenagers in the household (Teenager), and age of the head of
the household (Age).
The Minitab output is given below:
Referring to Table 17-12, what is the p-value of the test statistic when testing whether
Age makes a significant contribution to the model in the presence of the other
independent variables?
The Commissioner of Health in New York State wanted to study malpractice litigation
in New York. A sample of 31 thousand medical records was drawn from a population of
2.7 million patients who were discharged during 2010. Using the information obtained
from the sample to predict population characteristics with respect to malpractice
litigation is an example of ________.
TABLE 5-10
An accounting firm in a college town usually recruits employees from two of the
universities in town. This year, there are fifteen graduates from University A and five
from University B and the firm decides to hire six new employees from the two
universities.
Referring to Table 5-10, what is the probability that no more than four of the new
employees will be from University A?
TABLE 11-11
A student team in a business statistics course designed an experiment to investigate
whether the brand of bubblegum used affected the size of bubbles they could blow. To
reduce the person-to-person variability, the students decided to use a randomized block
design using themselves as blocks.
Four brands of bubblegum were tested. A student chewed two pieces of a brand of gum
and then blew a bubble, attempting to make it as big as possible. Another student
measured the diameter of the bubble at its biggest point. The following table gives the
diameters of the bubbles (in inches) for the 16 observations.
Referring to Table 11-11, is it appropriate to use the Tukey multiple comparison
procedure based on the test result above?
TABLE 5-7
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 houses are sold in 10 years has the following
probability distribution:
Referring to Table 5-7, if you can invest 10% of your money on the house in
neighborhood A and the remaining on the house in neighborhood B, what is the
portfolio risk of your investment?
TABLE 9-10
A manufacturer produces light bulbs that have a mean life of at least 500 hours when
the production process is working properly. Based on past experience, the population
standard deviation is 50 hours and the light bulb life is normally distributed. The
operations manager stops the production process if there is evidence that the population
mean light bulb life is below 500 hours.
Referring to Table 9-10, if you select a sample of 100 light bulbs and are willing to have
a level of significance of 0.10, the probability of a Type I error is ________ if the
population mean bulb life is 510 hours.