Two independent samples of
sizes n1 = 50 and n2 = 50
are randomly selected from two populations to test the difference between
the population means, . The sampling distribution of the sample
mean difference, is:
A.approximately
normal
B.chi-squared
distributed with 99 degrees of freedom
C.t
- distributed with 98 degrees of freedom
D.normally
distributed
Answer K
Question 2 of 17
0.0/
1.0 Points
A pharmaceutical company is
testing the effectiveness of a new drug for lowering cholesterol. As
part of this trial, they wish to determine whether there is a difference
between the effectiveness for women and for men. Assume α =
0.05. What is the test value?
Women
Men
Sample size
50
80
Mean effect
7
6.95
Sample variance
3
4
A.t
= 0.151
B.z
= 0.081
C.z
= 0.455
D.t
= 3.252
Feedback: This is a
t-test of independent samples. To compue the test value t use:
Question 3 of 17
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1.0 Points
Which of the following
statements is true regarding the F – distribution?
A.It
is a distribution of negative values
B.It
is always skewed to the left
C.It
typically appears in tests of equal proportions
D.none
of the above
Part
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Question 4 of 17
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1.0 Points
The correlation value ranges
from
A.-3
to +3
B.–1
to +1
C.0
to +1
D.–2
to +2
Answe
Question 5 of 17
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1.0 Points
Data for a sample of 25 apartments in a particular neighborhood are
provided in the worksheet Apartments in the Excel workbook Apartments.xlsx.
Using that data, find the estimated regression equation which can be
used to estimate the monthly rent for apartments in this neighborhood using
size as the predictor variable.
If an estimated regression line
has a Y-intercept of –7.5 and a slope of 2.5, then when X = 3, the actual
value of Y is:
A.5
B.10
C.0
D.unknown
Answer
Question 7 of 17
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1.0 Points
A
Question 8 of 17
1.0/
1.0 Points
Part
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Question 9 of 17
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2.0 Points
Accepted
characters: numbers, decimal point markers (period or
comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),
"E" or "e" (used in scientific notation). NOTE: For scientific notation, a period
MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and
"b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas
{9i} is not.
A field researcher is gathering data on the trunk diameters of mature pine
and spruce trees in a certain area. The following are the results of
his random sampling. Can he conclude, at the 0.10 level of
significance, that the average trunk diameter of a pine tree is greater
than the average diameter of a spruce tree?
Pine
trees
Spruce
trees
Sample size
30
35
Mean trunk diameter (cm)
45
39
Sample variance
120
140
What is the test value for this hypothesis test?
Test value: 2.474 Round
your answer to three decimal places.
What is the critical value?
Critical value: 1.296 Round
your answer to three decimal places.
Feedback: This is a
t-test of independent samples. Use the formula for the t test value
on page 480:
Using Table F (df = 29, alpha = 0.10, one-tail test) the critical t-value
is 1.311.
Part
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Question 10 of 17
1.0/
1.0 Points
Accepted
characters: numbers, decimal point markers (period or
comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),
"E" or "e" (used in scientific notation). NOTE: For scientific notation, a period
MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and
"b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas
{9i} is not.
Data for a sample of 25 apartments in a particular neighborhood are
provided in the worksheet Apartments in the Excel workbook
Apartments.xlsx. Using the estimated regression equation found by
using size as the predictor variable, find a point estimate for the average
monthly rent for apartments having 1,000 square feet of space. Place
your answer, rounded to the nearest
whole dollar, in the blank. 1242 When
entering your answer do not use any labels or symbols. Simply provide
the numerical value. For example, 123 would be a legitimate entry.
Accepted
characters: numbers, decimal point markers (period or
comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),
"E" or "e" (used in scientific notation). NOTE: For scientific notation, a period
MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and
"b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas
{9i} is not.
A company has observed that there is a linear relationship between indirect
labor expense (ILE) , in dollars, and direct labor hours (DLH). Data for
direct labor hours and indirect labor expense for 18 months are given in
the file ILE_and_DLH.xlsx
Treating ILE as the response variable, use regression to fit a straight
line to all 18 data points.
Using your estimated regression output, predict the indirect labor expenses
for a month in which the company has 31 direct labor hours.
Place your answer, rounded to 1 decimal place, in the blank. Do
not use any stray punctuation marks or a dollar sign. For
example, 458.9 would be a legitimate entry. 525.4
A
Part
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Question 12 of 17
0.0/
1.0 Points
Accepted
characters: numbers, decimal point markers (period or
comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),
"E" or "e" (used in scientific notation). NOTE: For scientific notation, a period
MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and
"b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas
{9i} is not.
Are America's top chief executive officers (CEOs) really worth all that
money? One way to answer this question is to look at the annual company
percentage increase in revenue versus the CEO's annual percentage salary
increase in that same company. Suppose that a random sample of companies
yielded the following data:
percent change for
corporation
15
12
3
12
28
6
8
2
percent change for CEO
6
17
-4
12
32
-1
7
2
Do these data indicate that the population mean percentage increase in
corporate revenue is greater than the population mean percentage increase
in CEO salary? Use a 5% level of significance. What is the test value that
you would use to conduct this test of hypothesis? Place your answer,
rounded to 3 decimal places, in the blank. For example, 2.345 would
be a legitimate entry. 0.357
Question 13 of 17
0.0/
1.0 Points
Accepted
characters: numbers, decimal point markers (period or
comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),
"E" or "e" (used in scientific notation). NOTE: For scientific notation, a period
MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and
"b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas
{9i} is not.
Are America's top chief executive officers (CEOs) really worth all that
money? One way to answer this question is to look at the annual company
percentage increase in revenue versus the CEO's annual percentage salary
increase in that same company. Suppose that a random sample of companies
yielded the following data:
percent change for
corporation
15
12
3
12
28
6
8
2
percent change for CEO
6
17
-4
12
32
-1
7
2
Do these data indicate that the population mean percentage increase in
corporate revenue is greater than the population mean percentage increase
in CEO salary? Use a 5% level of significance. What is the critical value
that you would use to conduct this test of hypothesis? Place your answer,
rounded to 3 decimal places, in the blank. For example, 2.345 would be a
legitimate entry. 1.773
Part
6 of 8 -
1.0/
3.0 Points
Question 14 of 17
1.0/
3.0 Points
Accepted
characters: numbers, decimal point markers (period or
comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),
"E" or "e" (used in scientific notation). NOTE: For scientific notation, a period
MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and
"b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas
{9i} is not.
A professor gives an exam for which there are two versions, A and B.
Each student in the class is given one randomly selected version of
the exam. After the exam, the professor wishes to determine if there
is a difference in the level of difficulty of the two versions by
determining if there is a significant difference in the mean scores. Assume α =
0.05.
Version
A
Version
B
Sample size
45
65
Mean score
8.8
8.2
Sample variance
2.6
2.4
What is the test value for this hypothesis test?
Answer: 1.23 Round
your answer to two decimal places.
What is/are the critical value(s) for this hypothesis test? If there
are two critical values, give only the positive value.
Answer: 1.96 Round your
answer to two decimal places.
What is the conclusion for this hypothesis test? Choose one.
1. There is not sufficient evidence to show that one version of the
exam is more difficult than the other.
2. There is sufficient evidence to show that one version of the exam
is more difficult than the other.
Answer:
Feedback: This is a
t-test of independent samples. Use the formula on page 480 to compute the
test value t:
Note that the variance is given, not the standard deviation.
This is a two-tail test with alpha = 0.05, df = 44 (using the smaller
sample size) critical value is found using the Critical Values workbook
to be ±2.0154.
Because the test value falls in the noncritical region, there is NOT
sufficient evidence to show that one version is more difficult than the
other at the 0.05 level of significance.
Part
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Question 15 of 17
1.0/
1.0 Points
In conducting hypothesis
testing for difference between two means when samples are dependent (paired
samples), the variable under consideration is ; the sample mean
difference between the pairs.
True
False
Part
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Question 16 of 17
1.0/
1.0 Points
In a simple regression
analysis, if the standard error of estimate sest = 15
and the number of observations n = 10, then the sum of the residuals
squared must be 120.
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