A fiA 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 .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
40
70
Mean trunk diameter (cm)
45
39
Sample variance
100
150
A.
The data support the claim because the test value 2.78 is greater than
1.64.
B.
The data do not support the claim because the test value 1.29 is greater
than 1.28.
C.The
data do not support the claim because the test value 1.29 is less than
1.64.
D.The
data support the claim because the test value 2.78 is greater than 1.28.
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Question 2 of 17
1.0 Points
MeMembers of the general adult
population volunteer an average of 4.2 hours per week. A random sample
of 20 female college students and 18 male college students produced the
results given in the table below. At the .01 level of significance, is
there sufficient evidence to conclude that a difference exists between the
mean number of volunteer hours per week for male and female college
students?
Females
Males
Sample size
20
18
Sample mean
3.8
2.5
Sample variance
3.5
2.2
A.No,
because the test value 2.38 is greater than the critical value
B.No,
because the test value 2.38 does not exceed the critical value
C.No,
because the test value 2.90 is greater than the critical value
D.Yes,
because the test value 2.90 is greater than the critical value
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Question 3 of 17
1.0 Points
SoSome defendants in criminal proceedings plead
guilty and are sentenced without a trial, whereas others who plead innocent
are subsequently found guilty and then are sentenced. In recent years,
legal scholars have speculated as to whether sentences of those who plead
guilty differ in severity from sentences for those who plead innocent and
are subsequently judged guilty. Consider the data given below on
defendants accused of robbery, all of whom, by the way, had previous prison
records. At the .01 level of significance, do these data suggest that
the proportion of all defendants in these circumstances who plead guilty
and are sent to prison differs from the proportion who are sent to prison
after pleading innocent and being found guilty?
Plea
Guilty
Not Guilty
Number
judged guilty
n1 = 191
n2 = 64
Number
sentenced to prison
x1 = 101
x2 = 56
Sample
proportion
.529
.875
A.No,
because the test value -4.94 is outside the interval (-1.96, 1.96)
B.No,
because the test value -1.96 is inside the interval (-2.58, 2.58)
C.Yes,
because the test value 2.58 is inside the interval (-4.94, 4.94)
D.Yes,
because the test value -4.94 is outside the interval (-2.58, 2.58)
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Part 2
of 8 -
Question 4 of 17
1.0 Points
Outliers
are observations that
A.render
the study useless
B.lie
outside the sample
C.disrupt
the entire linear trend
D.lie
outside the typical pattern of points
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Question 5 of 17
1.0 Points
The
marketing manager of a large supermarket chain would like to use shelf
space to predict the sales of pet food. For a random sample of 12
similar stores, she gathered the following information regarding the shelf
space, in feet, devoted to pet food and the weekly sales in hundreds of
dollars. .
Store
1
2
3
4
5
6
Shelf
Space
5
5
5
10
10
10
Weekly
Sales
1.6
2.2
1.4
1.9
2.4
2.6
Store
7
8
9
10
11
12
Shelf
Space
15
15
15
20
20
20
Weekly
Sales
2.3
2.7
2.8
2.6
2.9
3.1
Compute the value of the sample correlation coefficient between weekly
sales and shelf space.
A.0.827
B.0.684
C.0.308
D.0.652
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Question 6 of 17
1.0 Points
In a
simple linear regression analysis, the following sum of squares are
produced:
=
400
= 80
=
320
The
proportion of the variation inYthat is explained by the
variation inXis:
A.20%
B.50%
C.25%
D.80%
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Question 7 of 17
1.0 Points
A
correlation value of zero indicates.
A.a
weak linear relationship
B.no
linear relationship
C.a
strong linear relationship
D.a
perfect linear relationship
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Question 8 of 17
1.0 Points
The
standard error of the estimate, sest, is essentially the
A.standard
deviation of the residuals
B.mean
of the explanatory variable
C.standard
deviation of the explanatory variable
D.mean
of the residuals
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Part 3
of 8 -
Question 9 of 17
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 survey of employees at a company finds that 32 of the 88 employees who
drive to work were ever late during the past year, and 18 of the 64
employees who took public transportation were ever late during the past
year. At? = 0.10, is there a
difference between the proportion of employees who drove who were ever late
and the proportion of employees who took public transportation who were
ever late?
Find the test value for the difference in the proportion of employees who
were ever late for work in the past year.
Answer: Round
your answer to two decimal places.
What is your decision for this test?
1. The test value is greater than the critical value of 1.960.
2. The test value is less than the critical value of 1.645.
3. The test value is greater than the critical value of 1.282.
4. The test value is less than the critical value of 1.960.
Answer:
Enter only a 1, 2, 3 or 4 for your answer.
Part 4
of 8 -
Question 10 of 17
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.
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.
Question 11 of 17
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.
The marketing manager of a large supermarket chain
would like to determine the effect of shelf space (in feet) on the weekly
sales of international food (in hundreds of dollars). A random sample of 12
equal –sized stores is selected, with the following results:
Store
Shelf
Space(X)
Weekly
Sales(Y)
1
10
2.0
2
10
2.6
3
10
1.8
4
15
2.3
5
15
2.8
6
15
3.0
7
20
2.7
8
20
3.1
9
20
3.2
10
25
3.0
11
25
3.3
12
25
3.5
Find the equation of the regression line for these data. What is the
value of the standard error of the estimate? Place your answer,
rounded to 3 decimal places, in the blank. Do not use a dollar
sign. For example, 0.345 would be a legitimate entry.
Part 5
of 8 -
Question 12 of 17
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
p-value associated with this test of hypothesis? Place your
answer, rounded to 3 decimal places, in the blank. For example, 0.134
would be a legitimate entry.
Question 13 of 17
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.
Q-Mart is interested in comparing its male and female customers. Q-Mart would
like to know if the amount of money spent by its female charge customers
differs, on average, from the amount spent by its male charge
customers. To answer this question, an analyst collected random samples of
25 female customers and 22 male customers.
Based on these samples, on average, the 25 women charge customers spent
$102.23 and the 22 men charge customers spent $86.46. Moreover, the sample
standard deviation of the amount charged by the 25 women was $93.393, and
the sample standard deviation of the amount charged by the 22 men was
$59.695.
Suppose, using a 10% level of significance, you wish to know if there
is sufficient evidence for Q-Mart to conclude that, on average, the amount
spent by women charge customers differs from the amount spent by men charge
customers. That is suppose you wish to test
H0:
versus H1:
Assuming that the amounts spent by male and female charge customers at
Q-Mart are normally distributed, based on the procedure advocated by
Bluman, 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, 0.123 would be a legitimate entry.
Part 6
of 8 -
Question 14 of 17
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.
Researchers conducted an experiment to measure the effect of a drug on
improving the quality of sleep as determined by how many more minutes of
REM sleep were measured for each participant. One group of participants
were given the experimental drug; the other (control) group was given a
placebo. Does the evidence indicate that the drug improved the amount of
REM sleep at a 0.01 level of significance? Answer each of the following
parts.
Experimental
group
Control
group
sample
size
35
50
mean
sleep improvement
12.8
9.1
sample
variance
56.3
61.2
What is the test value for this hypothesis test?
Answer:
Round your answer to two decimal places.
What is
the P-value for this hypothesis test?
Answer:
Round your answer to three decimal places.
What is the conclusion of this hypothesis test? Choose one.
1. There is sufficient evidence to show that the experimental drug
improved the quality of sleep.
2. There is not sufficient evidence to show that the experimental
drug improved the quality of sleep.
3. There is sufficient evidence to show that the quality of sleep is
different for the experimental drug than for the control drug.
4. There is not sufficient evidence to show that the control drug
decreased the quality of sleep.
Answer:
Enter only a 1, 2, 3 or 4 for your answer.
Part 7
of 8 -
Question 15 of 17
1.0 Points
When
testing the equality of two population variances, the test statistic is the
ratio of the population variances; namely .
True
False
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Part 8
of 8 -
Question 16 of 17
1.0 Points
In a
simple linear regression problem, the least squares line is y' = -3.2 +
1.3X, and the coefficient of determination is 0.7225. The coefficient of
correlation must be –0.85.
True
False
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Question 17 of 17
1.0 Points
In a
simple linear regression problem, if the coefficient of determination is
0.95, this means that 95% of the variation in the explanatory variable X
can be explained by regression.
=
400
= 80
=
320
versus H1: 
.
Solution: MATH STATISTIC 302