Exhibit 15-7
A regression model involving 4 independent variables and a sample of 15 periods
resulted in the following sum of squares.
SSR = 165
SSE = 60
Refer to Exhibit 15-7. The test statistic from the information provided is
a. 2.110
b. 3.480
c. 4.710
d. 6.875
Which of the following variables use the interval scale of measurement?
a. name of stock exchange
b. time
c. SAT scores
d. Social Security number
A target population is
a. the population from which the sample is actually selected
b. the population for which inferences are to be made
c. always the same as the sampled population
d. the same as the sample
Exhibit 10-10
The results of a recent poll on the preference of shoppers regarding two products are
shown below.
Refer to Exhibit 10-10. The point estimate for the difference between the two
population proportions in favor of this product is
a. 52
b. 100
c. 0.44
d. 0.02
Michael, Inc., a manufacturer of electric guitars, is a small firm with 50 employees. The
table below shows the hourly wage distribution of the employees.
a. How many employees receive hourly wages of at least $18?
b. What percentage of the employees has hourly wages of at least $18?
c. What percentage of the employees has hourly wages of less than $14?
X is a exponentially distributed random variable with a mean of 10. Use Excel to
calculate the following:
a. P(x 15)
b. P(8 x 12)
c. P(x 8)
In factorial designs, the response produced when the treatments of one factor interact
with the treatments of another in influencing the response variable is known as
a. main effect
b. replication
c. interaction
d. None of these alternatives is correct.
To construct an interval estimate for the difference between the means of two
populations when the standard deviations of the two populations are unknown, we must
use a t distribution with (let n1 be the size of sample 1 and n2 the size of sample 2)
a. (n1 + n2) degrees of freedom
b. (n1 + n2 – 1) degrees of freedom
c. (n1 + n2 – 2) degrees of freedom
d. n1 – n2 + 2
Of 300 female registered voters surveyed, 120 indicated they were planning to vote for
the incumbent president; while of 400 male registered voters, 140 indicated they were
planning to vote for the incumbent president.
a. Compute the test statistic.
b. At alpha = .05, test to see if there is a significant difference between the proportions
of females and males who plan to vote for the incumbent president. (Use the p-value
approach.)
Exhibit 10-4
The following information was obtained from independent random samples.
Assume normally distributed populations with equal variances.
Refer to Exhibit 10-4. The point estimate for the difference between the means of the
two populations is
a. 0
b. 2
c. 3
d. 15
Exhibit 9-3
Refer to Exhibit 9-3. If the test is done at a 5% level of significance, the null hypothesis
should
a. not be rejected
b. be rejected
c. Not enough information given to answer this question.
d. None of the other answers are correct.
Scott Bell Builders would like to predict the total number of labor hours spent framing a
house based on the square footage of the house. The following data has been compiled
on ten houses recently built.
a. Develop the least-squares estimated regression equation that relates framing labor
hours to house square footage.
b. Use the regression equation developed in part (a) to predict framing labor hours when
the house size is 3350 square feet.
A sample of 9 mothers was taken. The mothers were asked the age of their oldest child.
You are given their responses below.
a. Compute the mean.
b. Compute the variance.
c. Compute the standard deviation.
d. Compute the coefficient of variation.
e. Determine the 25th percentile.
f. Determine the median
g. Determine the 75th percentile.
h. Determine the range.
Experimental outcomes that are based on measurement scales such as time, weight, and
distance can be described by _____ random variables.
a. discrete
b. continuous
c. uniform
d. intermittent
Exhibit 10-6
The management of a department store is interested in estimating the difference
between the mean credit purchases of customers using the store’s credit card versus
those customers using a national major credit card. You are given the following
information.
Refer to Exhibit 10-6. A 95% confidence interval estimate for the difference between
the average purchases of the customers using the two different credit cards is
a. 49 to 64
b. 11.68 to 18.32
c. 125 to 140
d. 8 to 10
In order to test for the significance of a regression model involving 4 independent
variables and 36 observations, the numerator and denominator degrees of freedom
(respectively) for the critical value of F are
a. 4 and 36
b. 3 and 35
c. 4 and 31
d. 4 and 32
Exhibit 6-3
The weight of football players is normally distributed with a mean of 200 pounds and a
standard deviation of 25 pounds.
Refer to Exhibit 6-3. The probability of a player weighing more than 241.25 pounds is
a. 0.4505
b. 0.0495
c. 0.9505
d. 0.9010
A microcomputer manufacturer has developed a regression model relating his sales (y
in $10,000s) with three independent variables. The three independent variables are price
per unit (Price in $100s), advertising (ADV in $1,000s) and the number of product lines
(Lines). Part of the regression results is shown below.
a. Use the above results and write the regression equation that can be used to predict
sales.
b. If the manufacturer has 10 product lines, advertising of $40,000, and the price per
unit is $3,000, what is your estimate of their sales? Give your answer in dollars.
c. Compute the coefficient of determination and fully interpret its meaning.
d. At = 0.05, test to see if there is a significant relationship between sales and unit
price.
e. At = 0.05, test to see if there is a significant relationship between sales and the
number of product lines.
f. Is the regression model significant? (Perform an F test.)
g. Fully interpret the meaning of the regression (coefficient of price) per unit that is, the
slope for the price per unit.
h. What has been the sample size for this analysis?