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Homework
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Homework Assignment #34
Review Section 9.8
Page 782, Exercises: 1 – 45(EOO), 47
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 1
Homework, Page 782
1.
Identify whether the number described is a parameter or a
statistic.
a. The average score on last week’s quiz was 73.4.
Parameter
b. About 13% of the population is left-handed.
Statistic
c. In a study of laboratory rats, 93% became aggressive
when deprived of sleep.
Statistic
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 2
Homework, Page 782
Find the mean of the data set.
5.
{32.4, 48.1, 85.3, 67.2, 72.4, 55.3}
32.4  48.1  85.3  67.2  72.4  55.3
 60.117
6
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 3
Homework, Page 782
Find the mean of the indicated data.
9.
The number of moons.
0  0  1  2  61  33  26  13  1
 15.2
9
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Planet
Moons
Mercury
0
Venus
0
Earth
1
Mars
2
Jupiter
61
Saturn
33
Uranus
26
Neptune
13
Pluto
1
Slide 9- 4
Homework, Page 782
13.
Determine the average annual home run production for
Willie Mays and for Mickey Mantle for their career totals of 660
over 22 years and 536 over 18 years, respectively. Who had the
greater production rate?
660
Mays :
 30.0
22
536
Mantle :
 29.78
18
Willie Mays had the better production rate.
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 5
Homework, Page 782
17.
Find the median and mode of the numbers in the table.
79.5
82.1
88.2
88.0
85.4
87.5
82.3
88.2
91.1
94.4
88.5
85.7
82.9
91.8
91.3
89.2
89.8
89.8
87.0
86.4
91.6
84.0
89.2
87.7
85.7
84.5
84.8
94.1
88.0
86.0
Mean = 84.823
There is no mode, as five numbers appear two times each and
none appear more than two times.
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 6
Homework, Page 782
21.
Use the data in the table to find:
A) The average (mean) monthly low temperatures for Beijing.
9    7    1  7  13  18  22  21  14  7   1   7 

Avg. Monthly Low 
12
 6.42C
B) Find the weighted average using the days in the month and
assuming no leap year.
31 9   28  7   31 1  30 7  31 13  30 18
Avg. Monthly Low 
31 22  31 21  30 14  31 7  30  1  31 7 
365
 6.49C
C) Compare the results above. Do the weights have an effect?
Why or why not? Which average is a better indicator?
The weights only have a slight effect because the numbers of
days per month vary slightly. The weighted average is better.
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 7
Homework, Page 782
Determine the five-number summary, the range, and the interquartile range for given data. Identify any outliers.
25. The following salaries for the employees in one department
of the Garcia Brothers Co. (in thousands of dollars): 33.5, 35.3,
33.8, 29.3, 36.7, 32.8, 31.7, 37.3, 33.5, 28.2, 34.8, 33.5, 29.7,
38.5, 32.7, 34.8, 34.2, 31.6, 35.4
To find the five-number summary, first arrange the numbers in
ascending order: 28.2, 29.3, 29.7, 31.6, 31.7, 32.7, 32.8, 33.5,
33.5, 33.5, 33.8, 34.2, 34.8, 34.8, 35.3, 35.4, 36.7, 37.3, 38.5
The minimum is 28.2, the median is 33.5, the first quartile is
31.7, the third quartile is 35.3, and the maximum is 38.5. The
five number summary is: 28.2,31.7,33.5,35.3,38.5 ; the range
is 10.3, the interquartile range is 3.6, and there are no outliers.
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 8
Homework, Page 782
Refer to the wind speed data in exercise 24.
29. Some wind turbine generators, to be efficient generators of
power, require average wind speeds of at least 10.5 mph.
Approximately what fraction of the climatic centers are suited for
these wind turbine generators?
Of the 44 centers, 12 or 3/11 of the climatic centers are suited for
these wind turbine generators.
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 9
Homework, Page 782
Find the standard deviation and variance of the data set.
33. {23, 45, 29, 34, 39, 41, 19, 22}
standard deviation,   9.0829
variance,  2  82.50
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 10
Homework, Page 782
Find the standard deviation and variance of the data set.
37. The data in exercise 24.
standard deviation,   11.9597
variance,  2  143.035
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 11
Homework, Page 782
41. In 1995, scores on the Scholastic Aptitude Test were re-scaled
to their original mean of 500 with an approximate standard
deviation of 100. SAT scores in the general population have a
normal distribution.
A) Approximately what percentage of 1995 scores fell between 400
and 600.
Approximately 68% percent of the scores fell between 400 and 600.
B) Approximately what percentage of 1995 scores fell below 300?
Approximately 2.5% percent of the scores fell below 300.
C) By 2001, the national average on the SAT Math section was 514.
Is this number a parameter or statistic?
The number 514 is a parameter, since it applies to the entire
population.
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 12
Homework, Page 782
45.
A)
B)
C)
D)
E)
The plot of a normal distribution will be
symmetric
skewed left
skewed right
lower in the middle than at the ends
of no predictable shape
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 13
Homework, Page 782
47.
Professor Mitchell grades the exams of his 30 students and
finds the scores have a mean of 81.3 and a median of 80.5. He later
determines that the top student deserves 9 extra points for a
misgraded proof. After the error is corrected, the scores have
A)
a mean of 81.3 and a median of 80.5
B)
a mean of 81.6 and a median of 80.5
C)
a mean of 81.6 and a median of 80.8
D)
a mean of 90.3 and a median of 80.5
E)
a mean of 90.3 and a median of 89.5
81.3  30   9  81.6, median is unchanged as only
30
the top grade increased.
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 14
Homework
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Homework Assignment #35
Review Sections 9.1 – 9.8
Page 786, Exercises: 1 – 113 (EOO)
Chapter 9 test next time
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 9- 15