Part 5 of 9 - Question 13 of 25 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 following data represent the number of children in a sample of 10 families from Chicago: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2. Compute the variance of the data. Place your answer, rounded to two decimal places, in the blank. For example, 3.45 would be a legitimate entry. Part 6 of 9 - Question 14 of 25 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 following data were obtained from a survey of college students. The variable X represents the number of non-assigned books read during the past six months. x 0 1 2 3 4 5 6  P (X=x) 0.55 0.15 0.10 0.10 0.04 0.03 0.03 Find P(1 < X < 5).  Place your answer, rounded to two decimal places in the blank.  For example, 0.56 would be a legitimate entry.  Question 15 of 25 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. In February 2002 the Argentine peso lost 70% of its value compared to the United States dollar. This devaluation drastically raised the price of imported products. According to a survey conducted by AC Nielsen in April 2002, 68% of the consumers in Argentina were buying fewer products than before the devaluation, 24% were buying the same number of products, and 8% were buying more products. Furthermore, in a trend toward purchasing less-expensive brands, 88% indicated that they had changed the brands they purchased. Suppose the following complete set of results were reported. Use the following data to answer this question.   Number of Products Purchased Brands Purchased Fewer Same More Total Same 10 14 24 48 Changed 262 82 8 352 Total 272 96 32 400   What is the probability that a consumer selected at random purchased fewer products than before? Place.

1. Part 5 of 9 -
Question 13 of 25
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 following data represent the number of children in a sample
of 10 families from Chicago: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2.
Compute the variance of the data. Place your answer, rounded to
two decimal places, in the blank. For example, 3.45 would be a
legitimate entry.
Part 6 of 9 -
Question 14 of 25
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.

2. 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 following data were obtained from a survey of college
students. The variable X represents the number of non-assigned
books read during the past six months.
x
0
1
2
3
4
5
6
P (X=x)
0.55
0.15
0.10
0.10
0.04
0.03
0.03
Find P(1 < X < 5). Place your answer, rounded to two decimal
places in the blank. For example, 0.56 would be a legitimate
entry.
Question 15 of 25
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).

3. 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.
In February 2002 the Argentine peso lost 70% of its value
compared to the United States dollar. This devaluation
drastically raised the price of imported products. According to a
survey conducted by AC Nielsen in April 2002, 68% of the
consumers in Argentina were buying fewer products than before
the devaluation, 24% were buying the same number of products,
and 8% were buying more products. Furthermore, in a trend
toward purchasing less-expensive brands, 88% indicated that
they had changed the brands they purchased. Suppose the
following complete set of results were reported. Use the
following data to answer this question.
Number of Products Purchased
Brands Purchased
Fewer
Same
More
Total
Same
10
14
24
48
Changed
262
82
8
352

4. Total
272
96
32
400
What is the probability that a consumer selected at random
purchased fewer products than before? Place your answer,
rounded to 4 decimal places, in the blank.
Part 7 of 9 -
Question 16 of 25
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.
An urn contains 12 balls identical in every respect except their
color. There are 3 red balls, 7 green balls, and 2 blue balls. You
draw two balls from the urn, but replace the first ball before
drawing the second. Find the probability that the first ball
drawn is red and the second ball drawn is green. Place your
answer, rounded to 4 decimal places, in the blank. For example,
0.4567 would be a legitimate entry.
Question 17 of 25
1.0 Points

5. 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.
An ice cream vendor sells three flavors: chocolate, strawberry,
and vanilla. Forty five percent of the sales are chocolate, while
30% are strawberry, with the rest vanilla flavored. Sales are by
the cone or the cup. The percentages of cones sales for
chocolate, strawberry, and vanilla, are 75%, 60%, and 40%,
respectively. For a randomly selected sale, define the following
events:
= chocolate chosen
= strawberry chosen
= vanilla chosen
= ice cream on a cone
ice cream in a cup
Find the probability that the ice cream was vanilla flavor, given
that it was sold on a cone. Place your answer, rounded to 4
decimal places, in the blank. For example, 0.3456 would be a
legitimate entry.
Part 8 of 9 -
Question 18 of 25
1.0 Points

6. 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 length of time to complete a door assembly on an
automobile factory assembly line is normally distributed with
mean 6.7 minutes and standard deviation 2.2 minutes. For a
door selected at random, what is the probability the assembly
line time will be between 5 and 10 minutes? Place your answer,
rounded to 4 decimal places, in the blank. For example, 0.1776
would be a legitimate answer.
Question 19 of 25
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 set of final exam scores in an organic chemistry course was
found to be normally distributed, with a mean of 73 and a
standard deviation of 8.

7. What is the probability of getting a score higher than 71 on this
exam? Place your answer, rounded to 4 decimal places in the
blank. For example, 0.3456 would be a legitimate entry.
Question 20 of 25
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 popular retail store knows that the purchase amounts by its
customers is a random variable that follows a normal
distribution with a mean of $30 and a standard deviation of $9.
What is the probability that a randomly selected customer will
spend $30 or more at this store? Place your answer, rounded to
4 decimal places, in the blank. For example, 0.3456 would be a
legitimate entry.
Question 21 of 25
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.

8. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is
valid whereas {9i} is not.
A set of final exam scores in an organic chemistry course was
found to be normally distributed, with a mean of 73 and a
standard deviation of 8.
What is the probability of getting a score of 91 or less on this
exam? Place your answer, rounded to 4 decimal places in the
blank. For example, 0.3456 would be a legitimate entry.
Question 22 of 25
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.
Suppose that the average weekly earnings for employees in
general automotive repair shops is $450, and that the standard
deviation for the weekly earnings for such employees is $50. A
sample of 100 such employees is selected at random.
Find the standard deviation of the sampling distribution of the
means of average weekly earnings for samples of size 100.
Place your answer in the blank. Do not include a dollar sign.
For example, 7 would be a legitimate entry.
Question 23 of 25
1.0 Points

9. 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 set of final exam scores in an organic chemistry course was
found to be normally distributed, with a mean of 73 and a
standard deviation of 8.
Only 5% of the students taking the test scored higher than what
value? Place your answer, rounded to a whole number, in the
blank. For example, 78 would be a legitimate entry.
Part 9 of 9 -
Question 24 of 25 1.0 Points
If Z is a standard normal variable, then P(Z > 1.50) = 0.9332
6
Q1
A simple random sample of 31 observations is derived from a
normally distributed population with a known standard
deviation of 2.3. Use Table 1.
a.

10. Is the condition that is normally distributed satisfied?
Yes
No
b.
Compute the margin of error with 94% confidence. (Do not
round intermediate calculations. Round "z" value to 3 decimal
places and final answer to 2 decimal places.)
Margin of error
c.
Compute the margin of error with 97% confidence. (Do not
round intermediate calculations. Round "z" value to 3 decimal
places and final answer to 2 decimal places.)
Margin of error
d.
Which of the two margins of error will lead to a wider interval?
The margin of error with 2.3% confidence.
The margin of error with 97% confidence.

11. Q2.
Consider a normal population with an unknown population
standard deviation. A random sample results in = 52.23 and s2 =
22.09. UseTable 2.
a.
Compute a 88% confidence interval for μ if and s2 were
obtained from a sample of 15 observations. (Do not round
intermediate calculations. Round "tα/2,df" value to 3 decimal
places and final answers to 2 decimal places.)
Confidence interval
to
b.
Compute a 88% confidence interval for μ if and s2 were
obtained from a sample of 24 observations. (Do not round
intermediate calculations. Round "tα/2,df" value to 3 decimal
places and final answers to 2 decimal places.)
Confidence interval
to
Q3.
A recent study found that consumers are making average
monthly debt payments of $983 (Experian.com, November 11,
2010). The accompanying table shows the average debt
payments for 26 metropolitan areas. Use Table 2.

12. City
Debt Payments
Washington, D.C.
$1,285
Seattle
1,135
Baltimore
1,133
Boston
1,133
Denver
1,104
San Francisco
1,098
San Diego
1,076
Sacramento
1,045
Los Angeles
1,024
Chicago
1,017
Philadelphia
1,011
Minneapolis
1,011
New York
989
Atlanta
986
Dallas
970
Phoenix
957
Portland
948

13. Cincinnati
920
Houston
889
Columbus
888
St. Louis
886
Miami
867
Detroit
832
Cleveland
812
Tampa
791
Pittsburgh
763
SOURCE: http://www.Experian.com, November 11, 2010.
Click here for the Excel Data File
a.
Use Excel to calculate the mean and standard deviation for debt
payments. (Do not round intermediate calculations. Round your
answers to 2 decimal places.)
Sample mean
Sample standard deviation
b.

14. Construct a 90% and a 95% confidence interval for the
population mean. (Do not round intermediate calculations.
Round "tα/2,df" value to 3 decimal places and final answers to 2
decimal places.)
Confidence Level
Confidence Interval
90%
to
95%
to
Q4.
One in five 18-year-old Americans has not graduated from high
school (The Wall Street Journal, April 19, 2007). A mayor of a
northeastern city comments that its residents do not have the
same graduation rate as the rest for the country. An analyst
from the Department of Education decides to test the mayor’s
claim. In particular, she draws a random sample of 80 18-year-
olds in the city and finds that 20 of them have not graduated
from high school. Use Table 1.
a.
Compute the point estimate for the proportion of 18-year-olds
who have not graduated from high school in this city. (Do not
round intermediate calculations. Round your answer to 2
decimal places.)
Point estimate

15. b.
Use this point estimate to derive a 95% confidence interval for
the population proportion. (Do not round intermediate
calculations. Round "z" value to 2 decimal places and final
answers to 3 decimal places.)
Confidence interval
to
Q5.
An analyst from an energy research institute in California
wishes to precisely estimate a 95% confidence interval for the
average price of unleaded gasoline in the state. In particular,
she does not want the sample mean to deviate from the
population mean by more than $0.06. What is the minimum
number of gas stations that she should include in her sample if
she uses the standard deviation estimate of $0.26, as reported in
the popular press? Use Table 1. (Do not round intermediate
calculations. Round "z" value to 2 decimal places. Round up
your answer to the nearest whole number.)
Minimum number of gas stations
Q6.
A simple random sample of 37 observations is derived from a
normally distributed population with a known standard
deviation of 6.4. Use Table 1.
a.
Is the condition that is normally distributed satisfied?

16. Yes
No
b.
Compute the margin of error with 99% confidence. (Round
intermediate calculations to 4 decimal places, "z" value and
final answer to 2 decimal places.)
Margin of error
c.
Compute the margin of error with 95% confidence. (Round
intermediate calculations to 4 decimal places, "z" value and
final answer to 2 decimal places.)
Margin of error
Q7.
Consider a population with a known standard deviation of 11.2.
In order to compute an interval estimate for the population
mean, a sample of 43 observations is drawn. Use Table 1.
a.
Is the condition that is normally distributed satisfied?
Yes

17. No
b.
Compute the margin of error at a 90% confidence level. (Round
your intermediate calculations to 4 decimal places. Round "z"
value and final answer to 2 decimal places.)
Margin of error
c.
Compute the margin of error at a 90% confidence level based on
a larger sample of 470 observations. (Round your intermediate
calculations to 4 decimal places. Round "z" value and final
answer to 2 decimal places.)
Margin of error
d.
Which of the two margins of error will lead to a wider
confidence interval?
90% confidence with n = 43.
90% confidence with n = 470.
Q8.
A family is relocating from St. Louis, Missouri, to California.
Due to an increasing inventory of houses in St. Louis, it is
taking longer than before to sell a house. The wife is concerned

18. and wants to know when it is optimal to put their house on the
market. They ask their realtor friend for help and she informs
them that the last 16 houses that sold in their neighborhood took
an average time of 250 days to sell. The realtor also tells them
that based on her prior experience, the population standard
deviation is 55 days. Use Table 1.
a.
What assumption regarding the population is necessary for
making an interval estimate for the population mean?
Assume that the central limit theorem applies.
Assume that the population has a normal distribution.
b.
Construct a 90% confidence interval for the mean sale time for
all homes in the neighborhood. (Round intermediate
calculations to 4 decimal places, "z" value and final answer to 2
decimal places.)
Confidence interval
to
Q9.
Find tα,df from the following information. Use Table 2. (Round
your answers to 3 decimal places.)
tα,df

19. a. α = 0.005 and df = 25
b. α = 0.20 and df = 25
c. α = 0.005 and df = 10
d. α = 0.20 and df = 10
Q10.
A random sample of 26 observations is used to estimate the
population mean. The sample mean and the sample standard
deviation are calculated as 125.4 and 26.50, respectively.
Assume that the population is normally distributed. Use Table
2.
a.
Construct a 95% confidence interval for the population mean.
(Round intermediate calculations to 4 decimal places, "t" value
to 3 decimal places, and final answers to 2 decimal places.)
Confidence interval
to
b.
Construct a 99% confidence interval for the population mean.
(Round intermediate calculations to 4 decimal places, "t" value
to 3 decimal places, and final answers to 2 decimal places.)
Confidence interval
to

20. Q11.
Let the following sample of 8 observations be drawn from a
normal population with unknown mean and standard deviation:
15, 25, 12, 18, 28, 17, 14, 24. Use Table 2.
a.
Calculate the sample mean and the sample standard deviation.
(Round intermediate calculations to 4 decimal places, "sample
mean" to 3 decimal places and "sample standard deviation" to 2
decimal places.)
Sample mean
Sample standard deviation
b.
Construct the 95% confidence interval for the population mean.
(Round "t" value to 3 decimal places, and final answers to 2
decimal places.)
Confidence interval
to
c.
Construct the 99% confidence interval for the population mean.
(Round "t" value to 3 decimal places, and final answers to 2
decimal places.)
Confidence interval

21. to
Q12.
The manager of The Cheesecake Factory in Boston reports that
on six randomly selected weekdays, the number of customers
served was 200, 145, 125, 260, 220, and 100. She believes that
the number of customers served on weekdays follows a normal
distribution. Construct a 95% confidence interval for the
average number of customers served on weekdays. Use Table
2. (Round intermediate calculations to 4 decimal places,
"sample mean" and "sample standard deviation" to 2 decimal
places and "t" value to 3 decimal places, and final answers to 2
decimal places.)
Confidence interval
to
Q13.
A random sample of 170 observations results in 119 successes.
Use Table 1.
a.
Construct a 99% confidence interval for the population
proportion of successes. (Round intermediate calculations to 4
decimal places, "z" value to 2 decimal places, and final answers
to 3 decimal places.)
Confidence interval
to
b.
Construct a 99% confidence interval for the population
proportion of failures. (Round intermediate calculations to 4

22. decimal places, "z" value to 2 decimal places, and final answers
to 3 decimal places.)
Confidence interval
to
Q14.
An economist reports that 882 out of a sample of 1,800 middle-
income American households actively participate in the stock
market.Use Table 1.
a.
Construct a 90% confidence interval for the proportion of
middle-income Americans who actively participate in the stock
market. (Round intermediate calculations to 4 decimal places,
"z" value to 2 decimal places, and final answers to 3 decimal
places.)
Confidence interval
to
Q15.
An accounting professor is notorious for being stingy in giving
out good letter grades. In a large section of 130 students in the
fall semester, she gave out only 5% As, 28% Bs, 38% Cs, and
29% Ds and Fs. Assuming that this was a representative class,
compute a 95% confidence interval of the probability of getting
at least a B from this professor. Use Table 1. (Round
intermediate calculations to 4 decimal places, "z" value to 2
decimal places, and final answers to 3 decimal places.)
Confidence interval
to

23. Q16.
In the planning stage, a sample proportion is estimated as =
18/30 = 0.60. Use this information to compute the minimum
sample size n required to estimate p with 95% confidence if the
desired margin of error E = 0.11. What happens to n if you
decide to estimate p with 90% confidence? UseTable 1. (Round
intermediate calculations to 4 decimal places and "z" value to 2
decimal places. Round up your answers to the nearest whole
number.)
Confidence Level
n
95%
90%