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Quantative Methods .docx Download Attachment
1.
1. The median is often a better representative of the central value of a data set
when the data set:
•
•
•
•
Source
Is bimodal.
Has a high standard deviation.
Is highly skewed.
2. The...1.
1. The median is often a better representative of the central value of a data set
when the data set:
•
•
•
•
Source
Is bimodal.
Has a high standard deviation.
Is highly skewed.
2. The data in the Excel spreadsheet linked below provide information on the
nutritional content (in grams per serving) of some leading breakfast cereals. For
which nutrients is the mean nutrient content per serving greater than the median
nutrient content per serving?
•
•
•
Breakfast Cereals
Source
Proteins only.
Complex carbohydrates only.
Both nutrients.
Neither nutrient.Has no outliers.
3.
3 The histogram below plots the carbon monoxide (CO) emissions (in
pounds/minute) of 40 different airplane models at takeoff. The distribution is best
described as is:
Source
•
•
•
Uniform.
Heteroskedastic.
Normal.
Skewed right.
4.
4. The histogram below plots the carbon monoxide (CO) emissions (in
pounds/minute) of 40 different airplane models at takeoff. Which of the following
statements is the best inference that can be drawn from this histogram?
Source
•
•
•
The mean amount of carbon monoxide emissions is greater than the
median amount of carbon monoxide emissions.
The mean amount of carbon monoxide emissions is less than the median
amount of carbon monoxide emissions.
The mean and median amounts of carbon monoxide emissions are about
equal.
The relative sizes of the mean and median amounts of carbon monoxide
emissions cannot be inferred from the histogram
5. In the data set shown below, the correlation coefficient of the two variables is:
Correlation Data
Source
•
1.0.
•
•
0.5
0.0
None of the above
6.
The data in the Excel spreadsheet linked below give the ages and salaries of the
chief executive officers of 59 companies with sales between $5 million and $350
million. The correlation between age and salary can be characterized as:
•
•
•
CEO Salaries
Source
Strong and positive.
Strong and negative.
Weak and positive.
Weak and negative.
7.
For a given set of data, the standard deviation measures:
•
•
•
Source
The difference between the mean and the data point farthest from the
mean.
The difference between the mean and the data point nearest to the mean.
The difference between the mean and the median.
None of the above.
8.
The data in the Excel spreadsheet linked below give the average exchange rates
of four currencies to the US dollar during October 2002. Over this period, which
currency was most volatile relative to the US dollar, as measured by the
coefficient of variation?
•
•
•
Exchange Rates
Source
The Brazilian Real.
The Euro.
The Japanese Yen.
The South Korean Won.
9.
A national business magazine intends to survey its subscribers to determine who
they think is the "CEO of the Century." Subscribers are invited to complete an
online survey. Based only on this information, which of the following can be
inferred about the survey results?
•
•
Source
They will be biased because the magazine's subscribers are unqualified to
determine who the CEO of the century is.
They will accurately reflect the opinion of the nation as a whole about who
the CEO of the century is.
•
They will be unbiased because the respondents will be selfselected.
They will be biased because subscribers who have access to the online
survey are not representative of the population of subscribers as a whole.
10. A political consultant conducts a survey to determine what position the
mayoral candidate she works for should take on a proposed smoking ban in
restaurants. Which of the following survey questions will deliver an unbiased
response?
•
•
•
Source
Should the city ban smoking in restaurants to protect our children from
secondhand smoke?
Should tobacco smoke, a known cause of lung cancer, be banned from
public spaces such as restaurants?
Does the city have the right to restrict recreational activities, such as
moderate consumption of alcohol or tobacco, on the premises of privatelyowned
businesses?
None of the above
11.
In a recently administered IQ test, the scores were distributed normally, with
mean 100 and standard deviation 15. What proportion of the test takers scored
between 70 and 130?
•
•
•
Source
About 68%.
About 84%.
About 95%.
About 99.5%.
12.
Which of the following is not true about the Normal Distribution?
•
•
•
Source
It is symmetric.
Its mean and median are equal.
It is completely described by its mean and its standard deviation.
It is bimodal.
13. The histogram below shows the underlying distribution pattern of the results
of a rolled die. Suppose the die is rolled 50 times and the results are averaged.
Suppose this process — rolling 50 dice and averaging their results — is repeated
100 times. Which of the following best describes the distribution of these 100
averages?
Source
•
•
•
Skewed right.
Skewed left.
Normal.
Uniform.
14.
A nutrition researcher wants to determine the mean fat content of hen's eggs.
She collects a sample of 40 eggs. She calculates a mean fat content of 23
grams, with a sample standard deviation of 8 grams. From these statistics she
calculates a 90% confidence interval of [20.9 grams, 25.1 grams]. What can the
researcher do to decrease the width of the confidence interval?
•
•
•
Source
Increase the confidence level.
Decrease the confidence level.
Decrease the sample size
None of the above
15.
In a random sample of 321 senior citizens, 61 were found to own a home
computer. Based on this sample, the 95% confidence interval for the proportion
of computerowners among senior citizens is:
•
•
•
Source
[2.6%; 7.4%].
[13.4%; 24.6%].
[14.7%; 23.3%].
The answer cannot be determined from the information given.
16.
Preliminary estimates suggest that about 58% of students at a state university
favor implementing an honor code. To obtain a 95% confidence interval for the
proportion of all students at the university favoring the honor code, what is the
minimum sample size needed if the total width of the confidence interval must be
less than 5 percentage points (i.e., the confidence interval should extend at most
2.5 percentage points above and below the sample proportion)?
•
•
•
Source
375.
264.
1,498.
The answer cannot be determined from the information given.
17.
In a survey of twelve Harbor Business School graduates, the mean starting
salary was $93,000, with a standard deviation of $17,000. The 95% confidence
interval for the average starting salary among all Harbor graduates is:
•
•
•
Source
[$83,382; $102,618].
[$82,727; $103,327].
[$82,199; $103,801].
[$59,000; $127,000].
18.
In a survey of 53 randomly selected patrons of a shopping mall, the mean
amount of currency carried is $42, with a standard deviation of $78. What is the
95% confidence interval for the mean amount of currency carried by mall
patrons?
•
•
•
Source
[$39.1; $44.9].
[$24.4; $59.6].
[$21.0; $63.0].
[$14.4; $69.6].
19.
A filling machine in a brewery is designed to fill bottles with 355 ml of hard cider.
In practice, however, volumes vary slightly from bottle to bottle. In a sample of 49
bottles, the mean volume of cider is found to be 354 ml, with a standard deviation
of 3.5 ml. At a significance level of 0.01, which conclusion can the brewer draw?
•
•
•
Source
The true mean volume of all bottles filled is 354 ml.
The machine is not filling bottles to an average volume of 355 ml.
There is not enough evidence to indicate that the machine is not filling
bottles to an average volume of 355 ml.
The machine is filling bottles to an average volume of 355 ml.
20. To conduct a onesided hypothesis test of the claim that houses located on
corner lots (cornerlot houses) have higher average selling prices than those
located on noncorner lots, the following alternative hypothesis should be used:
•
•
•
House Prices Data
Source
The average selling price of a cornerlot house is higher than it is
commonly believed to be.
The average selling price of a cornerlot house is higher than the average
selling price of all houses.
The average selling price of a cornerlot house is the same as the average
selling price of a house not located on a corner lot.
The average selling price of a cornerlot house is higher than the
average selling price of a house not located on a corner lot.
21. The data in the Excel spreadsheet linked below indicate the selling prices of
houses located on corner lots ("cornerlot houses") and of houses not located on
corner lots. Conduct a onesided hypothesis test of the claim that cornerlot
houses have higher average selling prices than those located on noncorner lots.
Using a 99% confidence level, which of the following statements do the data
support?
•
•
•
House Prices Data
Source
Upscale, expensive neighborhoods have more street corners.
The average selling price of a cornerlot house is higher than that of the
average house not located on a corner lot.
The average selling price of a cornerlot house is no more than that of the
average house not located on a corner lot.
There is not enough evidence to support the claim that the average
selling price of a cornerlot house is higher than that of the average house not
located on a corner lot.
22.
Two semiconductor factories are being compared to see if there is a difference in
the average defect rates of the chips they produce. In the first factory, 250 chips
are sampled. In the second factory, 350 chips are sampled. The proportions of
defective chips are 4.0% and 6.0%, respectively. Using a confidence level of
95%, which of the following statements is supported by the data?
•
•
•
Source
There is not sufficient evidence to show a significant difference in the
average defect rates of the two factories.
There is a significant difference in the average defect rates of the two
factories.
The first factory's average defect rate is lower than the second factory's on
95 out of 100 days of operation.
None of the above.
23.
The regression analysis below relates average annual per capita beef
consumption (in pounds) and the independent variable "average annual beef
price" (in dollars per pound). The coefficient on beef price tells us that:
Beef Consumption and Price
Source
•
•
•
For every price increase of $1, average beef consumption decreases by
9.31 pounds.
For every price increase of $1, average beef consumption increases by
9.31 pounds.
For every price increase $9.31, average beef consumption decreases by 1
pound.
For price increase of $9.31, average beef consumption increases by 1
pound.
24.
The regression analysis below relates average annual per capita beef
consumption (in pounds) and the independent variable "average annual beef
price" (in dollars per pound). In a year in which the average price of beef is at
$3.51 per pound, we can expect average annual per capita beef consumption to
be approximately:
Beef Consumption and Price
Source
•
•
•
55.2 pounds
52.6 pounds
53.6 pounds
117.9 pounds
25.
The regression analysis below relates average annual per capita beef
consumption (in pounds) and the independent variable "average annual per
capita pork consumption" (in pounds). At what level is the coefficient of the
independent variable pork consumption significant?
Beef Consumption and Pork Consumption
Source
•
•
•
0.10.
0.05.
0.01.
None of the above.
26.
The regression analysis below relates average annual per capita beef
consumption (in pounds) and the independent variable "average annual per
capita pork consumption" (in pounds). Which of the following statements is true?
Beef Consumption and Pork Consumption
Source
•
•
•
Beef consumption can never be less than 65.09 pounds.
Beef consumption can never be... View Full Attachment Show more
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1.
1. The median is often a better representative of the central value of a data set when the data set:
Source
Is bimodal.
Has a high standard deviation.
Is highly skewed.
Answer:
We usually...
"Precise and On Time. "

Qualitative methods 2,6,7,8,20,21.xls Download Attachment
Cereal
100% Bran
AllBran
Almond Delight
Apple Cinnamon Cheerios
Apple Jacks
Bran Chex
Bran Flakes
Cap'n'Crunch
Cheerios
Cinnamon Toast Crunch
Cocoa Puffs
Corn Chex
Corn Flakes
Corn Pops
Count...Cereal
100% Bran
AllBran
Almond Delight
Apple Cinnamon Cheerios
Apple Jacks
Bran Chex
Bran Flakes
Cap'n'Crunch
Cheerios
Cinnamon Toast Crunch
Cocoa Puffs
Corn Chex
Corn Flakes
Corn Pops
Count Chocula
Cracklin' Oat Bran
Cream of Wheat (Quick)
Crispix
Double Chex
Froot Loops
Frosted Flakes
Frosted MiniWheats
Fruit & Fibre Dates, Walnuts, and Oats
Fruity Pebbles
Golden Grahams
Grape Nuts Flakes
GrapeNuts
Great Grains Pecan
Honey Nut Cheerios
Honeycomb
Kix
Life
Lucky Charms
Maypo
Muesli Raisins, Dates, & Almonds
Muesli Raisins, Peaches, & Pecans
Mueslix Crispy Blend
Nut&Honey Crunch
Nutrigrain Wheat
Post Nat. Raisin Bran
Product 19
Puffed Rice
Puffed Wheat
Quaker Oat Squares
Raisin Bran
Raisin Nut Bran
Raisin Squares
Rice Chex
Rice Krispies
Shredded Wheat
Smacks
Special K
Total Corn Flakes
Total Raisin Bran
Total Whole Grain
Triples
Trix
Wheat Chex
Wheaties
Protein
(grams per
serving)
4
4
2
2
2
2
3
1
6
1
1
2
2
1
1
3
3
2
2
2
1
3
3
1
1
3
3
3
3
1
2
4
2
4
4
4
3
2
3
3
3
1
2
4
3
3
2
1
2
2
2
6
2
3
3
2
1
3
3
Complex
Carbohydrates
(grams per serving)
5
7
14
11
11
15
13
12
17
13
12
22
21
13
12
10
21
21
18
11
14
14
12
13
15
15
17
13
12
14
21
12
12
16
16
16
17
15
18
11
20
13
10
14
14
11
15
23
22
16
9
16
21
15
16
21
13
17
17
qattachments_3d022bb665f95d722f7c14e2353a8b843bee96cd.xls
Q2 Cereals
07/25/2014
Age
53
43
33
45
46
55
41
55
36
45
55
50
49
47
69
51
48
62
45
37
50
50
50
58
53
57
53
61
47
56
44
46
58
48
38
74
60
32
51
50
40
61
63
56
45
61
70
59
57
69
44
56
50
56
43
48
52
62
48
Salary
($thousands)
145
621
262
208
362
424
339
736
291
58
498
643
390
332
750
368
659
234
396
300
343
536
543
217
298
1103
406
254
862
204
206
250
21
298
350
800
726
370
536
291
808
543
149
350
242
198
213
296
317
482
155
802
200
282
573
388
250
396
572
qattachments_3d022bb665f95d722f7c14e2353a8b843bee96cd.xls
Q6,7 Salaries
07/25/2014
Date
10/1/2002
10/2/2002
10/3/2002
10/4/2002
10/5/2002
10/6/2002
10/7/2002
10/8/2002
10/9/2002
10/10/2002... View Full Attachment Show more

8466844.doc Download Attachment

8466844.doc Download Attachment
1.
1. The median is often a better representative of the central value of a data set when the data set:
Source
←
←
←
Answer:
Is bimodal.
Has a high standard deviation.
Is highly skewed.
We...1.
1. The median is often a better representative of the central value of a data set when the data set:
Source
←
←
←
Answer:
Is bimodal.
Has a high standard deviation.
Is highly skewed.
We usually prefer the median over the mean (or mode) is when our data is skewed
2. The data in the Excel spreadsheet linked below provide information on the nutritional content
(in grams per serving) of some leading breakfast cereals. For which nutrients is the mean nutrient
content per serving greater than the median nutrient content per serving?
Breakfast Cereals
Source
←
Proteins only.
←
Complex carbohydrates only.
←
Both nutrients.
Neither nutrient.Has no outliers.
Mean
2.49152542
4
Median
2
14.80508475
14
3.
3 The histogram below plots the carbon monoxide (CO) emissions (in pounds/minute) of 40
different airplane models at takeoff. The distribution is best described as is:
Source
←
←
Uniform.
Heteroskedastic.
←
Normal.
Skewed right.
Answer:
The distribution is best described as skewed right because the maximum number of airplane
models lies to the left of the histogram.
4.
4. The histogram below plots the carbon monoxide (CO) emissions (in pounds/minute) of 40
different airplane models at takeoff. Which of the following statements is the best inference that
can be drawn from this histogram?
Source
←
The mean amount of carbon monoxide emissions is greater than the
median amount of carbon monoxide emissions.
←
The mean amount of carbon monoxide emissions is less than the median
amount of carbon monoxide emissions.
←
The mean and median amounts of carbon monoxide emissions are about
equal.
The relative sizes of the mean and median amounts of carbon monoxide emissions cannot
be inferred from the histogram
Answer:
The relative sizes of the mean and median amounts of carbon monoxide emissions cannot be
inferred from the histogram
5. In the data set shown below, the correlation coefficient of the two variables is:
Correlation Data
Source
←
←
←
1.0.
0.5
0.0
None of the above
SUMMARY OUTPUT
Regression Statistics
Multiple R
1
R Square
1
Adjusted R
Square
1
2.22E
Standard Error
16
Observations
12
6.
The data in the Excel spreadsheet linked below give the ages and salaries of the chief executive
officers of 59 companies with sales between $5 million and $350 million. The correlation
between age and salary can be characterized as:
CEO Salaries
Source
←
Strong and positive.
←
Strong and negative.
←
Weak and positive.
Weak and negative.
Simple Linear Regression
Analysis
Regression Statistics
Multiple R
0.1276
R Square
0.0163
Adjusted R
Square
Standard Error
Observations
0.0010
220.642
5
59
7.
For a given set of data, the standard deviation measures:
Source
←
The difference between the mean and the data point farthest from the
mean.
←
←
The difference between the mean and the data point nearest to the mean.
The difference between the mean and the median.
None of the above.
8.
The data in the Excel spreadsheet linked below give the average exchange rates of four currencies
to the US dollar during October 2002. Over this period, which currency was most volatile relative
to the US dollar, as measured by the coefficient of variation?
Exchange Rates
Source
←
The Brazilian Real.
←
The Euro.
←
The Japanese Yen.
The South Korean Won.
Brazilian
Real per
Dollar
Standard deviation
Mean
Coefficient of
variation =
0.10452548
3.84
0.02719698
7
Japanese
Yen per
Dollar
0.95116058
1
124.01
0.00767019
1
Euro per
Dollar
0.00575423
1.02
0.00564313
3
South
Korean Won
per Dollar
12.1056238
6
1239.57
0.00976597
9
9.
A national business magazine intends to survey its subscribers to determine who they think is the
"CEO of the Century." Subscribers are invited to complete an online survey. Based only on this
information, which of the following can be inferred about the survey results?
Source
←
They will be biased because the magazine's subscribers are unqualified to
determine who the CEO of the century is.
←
They will accurately reflect the opinion of the nation as a whole about
who the CEO of the century is.
←
They will be unbiased because the respondents will be selfselected.
They will be biased because subscribers who have access to the online survey are not
representative of the population of subscribers as a whole.
Answer:
They will be biased because subscribers who have access to the online survey are not
representative of the population of subscribers as a whole.
10. A political consultant conducts a survey to determine what position the mayoral candidate she
works for should take on a proposed smoking ban in restaurants. Which of the following survey
questions will deliver an unbiased response?
Source
←
←
←
Should the city ban smoking in restaurants to protect our children from
secondhand smoke?
Should tobacco smoke, a known cause of lung cancer, be banned from
public spaces such as restaurants?
Does the city have the right to restrict recreational activities, such as
moderate consumption of alcohol or tobacco, on the premises of privatelyowned
businesses?
None of the above
Answer:
Should the city ban smoking in restaurants to protect our children from second hand smoke will
deliver an unbiased response.
11.
In a recently administered IQ test, the scores were distributed normally, with mean 100 and
standard deviation 15. What proportion of the test takers scored between 70 and 130?
Source
←
←
←
About 68%.
About 84%.
About 95%.
About 99.5%.
Probability for a Range
From X Value
70
To X Value
130
Z Value for 70
2
Z Value for 130
2
P(X<=70)
0.0228
P(X<=130)
0.9772
P(70<=X<=130)
0.9545
12.
Which of the following is not true about the Normal Distribution?
Source
←
←
←
It is symmetric.
Its mean and median are equal.
It is completely described by its mean and its standard deviation.
It is bimodal.
Answer:
Normal distribution is unimodal.
13. The histogram below shows the underlying distribution pattern of the results of a rolled die.
Suppose the die is rolled 50 times and the results are averaged. Suppose this process — rolling 50
dice and averaging their results — is repeated 100 times. Which of the following best describes
the distribution of these 100 averages?
Source
←
←
←
Skewed right.
Skewed left.
Normal.
Uniform.
Answer:
Since the probability remains the same on every result of die rolled, it is uniform distribution.
14.
A nutrition researcher wants to determine the mean fat content of hen's eggs. She collects a
sample of 40 eggs. She calculates a mean fat content of 23 grams, with a sample standard
deviation of 8 grams. From these statistics she calculates a 90% confidence interval of [20.9
grams, 25.1 grams]. What can the researcher do to decrease the width of the confidence interval?
Source
←
←
←
Increase the confidence level.
Decrease the confidence level.
Decrease the sample size
None of the above
Answer:
Researcher can decrease the confidence level to decrease the width of the confidence interval.
Width of 90% confidence interval is 25.1 – 20.9 = 4.2
Now, we decrease the confidence level to 80%, the confidence interval
23 ± 1.282*8/√40 = 21.4, 24.6
Width of 80% confidence interval is 24.6 – 21.4 = 3.2
Therefore, decrease in confidence level decreases the width.
15.
In a random sample of 321 senior citizens, 61 were found to own a home computer. Based on this
sample, the 95% confidence interval for the proportion of computerowners among senior citizens
is:
Source
←
←
←
[2.6%; 7.4%].
[13.4%; 24.6%].
[14.7%; 23.3%].
The answer cannot be determined from the information given.
Confidence Interval Estimate for the Proportion
Data
Sample Size
Number of Successes
Confidence Level
321
61
95%
Intermediate Calculations
0.19003115
Sample Proportion
3
Z Value
1.9600
Standard Error of the Proportion
0.0219
Interval Half Width
0.0429
Confidence Interval
Interval Lower Limit
Interval Upper Limit
0.1471
0.2329
16.
Preliminary estimates suggest that about 58% of students at a state university favor implementing
an honor code. To obtain a 95% confidence interval for the proportion of all students at the
university favoring the honor code, what is the minimum sample size needed if the total width of
the confidence interval must be less than 5 percentage points (i.e., the confidence interval should
extend at most 2.5 percentage points above and below the sample proportion)?
Source
←
←
←
375.
264.
1,498.
The answer cannot be determined from the information given.
Solution:
We have p = 0.58, E = 0.05 and α = 1 – 0.95 = 0.05
Using Ztables,
Z (α/2) = Z (0.05/2)
= Z (0.025)
=1.96
The sample size is given by:N = (Z/E) ² *p*(1 – p)
= (1.96/0.05)²*0.58*(1 – 0.58)
= 1536.64*0.58*0.42
= 374.33
= 375
17.
In a survey of twelve Harbor Business School graduates, the mean starting salary was $93,000,
with a standard deviation of $17,000. The 95% confidence interval for the average starting salary
among all Harbor graduates is:
Source
←
←
←
[$83,382; $102,618].
[$82,727; $103,327].
[$82,199; $103,801].
[$59,000; $127,000].
Confidence Interval Estimate for the
Mean
Data
Sample Standard
Deviation
17000
Sample Mean
Sample Size
Confidence Level
93000
12
95%
Intermediate Calculations
Standard Error of the
4907.47728
Mean
8
Degrees of Freedom
11
t Value
2.2010
Interval Half Width
10801.2847
Confidence Interval
Interval Lower Limit
82198.72
Interval Upper Limit
103801.28
18.
In a survey of 53 randomly selected patrons of a shopping mall, the mean amount of currency
carried is $42, with a standard deviation of $78. What is the 95% confidence interval for the mean
amount of currency carried by mall patrons?
Source
←
←
←
[$39.1; $44.9].
[$24.4; $59.6].
[$21.0; $63.0].
[$14.4; $69.6].
Confidence Interval Estimate for the
Mean
Data
Population Standard
Deviation
Sample Mean
Sample Size
Confidence Level
78
42
53
95%
Intermediate Calculations
10.7141239
Standard Error of the Mean
9
Z Value
1.9600
Interval Half Width
20.9993
Confidence Interval
Interval Lower Limit
Interval Upper Limit
21.00
63.00
19.
A filling machine in a brewery is designed to fill bottles with 355 ml of hard cider. In practice,
however, volumes vary slightly from bottle to bottle. In a sample of 49 bottles, the mean volume
of cider is found to be 354 ml, with a standard deviation of 3.5 ml. At a significance level of 0.01,
which conclusion can the brewer draw?
Source
←
←
←
The true mean volume of all bottles filled is 354 ml.
The machine is not filling bottles to an average volume of 355 ml.
There is not enough evidence to indicate that the machine is not filling
bottles to an average volume of 355 ml.
The machine is filling bottles to an average volume of 355 ml.
Z Test of Hypothesis for the Mean
Data
Null Hypothesis
=
Level of Significance
Population Standard Deviation
Sample Size
Sample Mean
355
0.01
3.5
49
354
Intermediate Calculations
Standard Error of the Mean
Z Test Statistic
0.500
0
2.000
0
TwoTail Test
Lower Critical Value
Upper Critical Value
pValue
Do not reject the null
hypothesis
2.575
8
2.575
8
0.045
5
20. To conduct a onesided hypothesis test of the claim that houses located on corner lots (cornerlot houses) have higher average selling prices than those located on noncorner lots, the following
alternative hypothesis should be used:
House Prices Data
Source
←
The average selling price of a cornerlot house is higher than it is
commonly believed to be.
←
The average selling price of a cornerlot house is higher than the average
selling price of all houses.
←
The average selling price of a cornerlot house is the same as the average
selling price of a house not located on a corner lot.
The average selling price of a cornerlot house is higher than the average selling
price of a house not located on a corner lot.
21. The data in the Excel spreadsheet linked below indicate the selling prices of houses located on
corner lots ("cornerlot houses") and of houses not located on corner lots. Conduct a onesided
hypothesis test of the claim that cornerlot houses have higher average selling prices than those
located on noncorner lots. Using a 99% confidence level, which of the following statements do
the data support?
House Prices Data
Source
←
Upscale, expensive neighborhoods have more street corners.
←
The average selling price of a cornerlot house is higher than that of the
average house not located on a corner lot.
←
The average selling price of a cornerlot house is no more than that of the
average house not located on a corner lot.
There is not enough evidence to support the claim that the average selling price
of a cornerlot house is higher than that of the average house not located on a corner lot.
PooledVariance t Test for the Difference
Between Two Means
(assumes equal population
variances)
Data
Hypothesized Difference
0
Level of Significance
0.05
Population 1 Sample
Sample Size
40
1146.72
Sample Mean
5
400.857
Sample Standard Deviation
7
Population 2 Sample
Sample Size
77
1019.10
Sample Mean
4
364.428
Sample Standard Deviation
2
Intermediate Calculations
Population 1 Sample Degrees of
Freedom
39
Population 2 Sample Degrees of
Freedom
Total Degrees of Freedom
Pooled Variance
Standard Error
Difference in Sample Means
t Test Statistic
UpperTail Test
Upper Critical Value
pValue
Reject the null hypothesis
76
115
142262.
5
73.5128
127.621
1
1.7360
1.6582
0.0426
22.
Two semiconductor factories are being compared to see if there is a difference in the average
defect rates of the chips they produce. In the first factory, 250 chips are sampled. In the second
factory, 350 chips are sampled. The proportions of defective chips are 4.0% and 6.0%,
respectively. Using a confidence level of 95%, which of the following statements is supported by
the data?
Source
←
←
←
There is not sufficient evidence to show a significant difference in the
average defect rates of the two factories.
There is a significant difference in the average defect rates of the two
factories.
The first factory's average defect rate is lower than the second factory's
on 95 out of 100 days of operation.
None of the above.
Answer:
Z Test for Differences in Two
Proportions
Data
Hypothesized Difference
Level of Significance
Group 1
Number of Items of
Interest
Sample Size
Group 2
Number of Items of
Interest
0
0.05
10
250
21
Sample Size
350
Intermediate Calculations
Group 1 Proportion
0.04
Group 2 Proportion
0.06
Difference in Two
Proportions
0.02
0.05166666
Average Proportion
7
Z Test Statistic
1.09112038
TwoTail Test
Lower Critical Value
Upper Critical Value
pValue
Do not reject the null
hypothesis
1.9600
1.9600
0.2752
23.
The regression analysis below relates average annual per capita beef consumption (in pounds)
and the independent variable "average annual beef price" (in dollars per pound). The coefficient
on beef price tells us that:
Beef Consumption and Price
Source
←
For every price increase of $1, average beef consumption decreases by
9.31 pounds.
←
For every price increase of $1, average beef consumption increases by
9.31 pounds.
←
For every price increase $9.31, average beef consumption decreases by 1
pound.
For price increase of $9.31, average beef consumption increases by 1 pound.
Answer:
←
Since the slope is 9.31, for every price increase of $1, average beef consumption
decreases by 9.31 pounds.
24.
The regression analysis below relates average annual per capita beef consumption (in pounds)
and the independent variable "average annual beef price" (in dollars per pound). In a year in
which the average price of beef is at $3.51 per pound, we can expect average annual per... View Full Attachment Show more
Precise and On Time.