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14
Humerus length (cm)
14.1 (a) See also the solution to Exercise 3.19. The correlation is r 0.994, and linear regression
3.660 1.1969x . The scatterplot below shows a strong, positive, linear relationgives y
ship
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13.1 (a) (i) 0.20
(ii) P 0.3172.
P
0.25. (ii) P
0.235. (b) (i) 0.02
P
0.025. (ii) P
0.0204. (c) (i) P
0.25.
13.2 H0: The marital-status distribution of 25- to 29-year-old U.S. males is the same as that of the
p
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12
12.1 (a) Population: the 175 residents of Tonyas dorm; p is the proportion who like the food.
(b) p 0.28.
12.2 (a) The population is the 2400 students at Glens college, and p is the proportion who believe
tuiti
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10
10.1 (a) 44% to 50%. (b) We do not have information about the whole population; we only know about a small sample. We expect our sample to give us a good estimate of the population value, but it will not be exa
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9
9.1
2.5003 is a parameter; x
9.2 p
7.2% is a statistic.
9.3 p
48% is a statistic; p
9.4 Both x1
335 and x2
2.5009 is a statistic.
52% is a parameter.
289 are statistics.
9.5 (a) Since the proportion of times the
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8
8.1 (a) No: There is no fixed n (i.e., there is no definite upper limit on the number of defects). (b) Yes: It is reasonable to believe that all responses are independent (ignoring any "peer pressure"), and all
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7
7.1 (a) P(less than 3) P(1 or 2)
2 6 1 3.
(b)(c) Answers vary.
7.2 (a) BBB, BBG, BGB, GBB, GGB, GBG, BGG, GGG. Each has probability 1/8. (b) Three of the eight arrangements have two (and only two) girls, so P(X
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6
6.1 Long trials of this experiment often approach 40% heads. One theory attributes this surprising result to a "bottle-cap effect" due to an unequal rim on the penny. We don't know. But a teaching assistan
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5
5.1 The population is employed adult women, the sample is the 48 club members who returned
the survey.
5.2 (a) An individual is a person; the population is all adult U.S. residents. (b) An individual is a
househo
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4.1 (a) Since 2.54 cm 1 inch, inches are changed to centimeters by multiplying by 2.54. Letting
x
height in inches and y
height in centimeters, the transformation is y
2.54x, which is
1
monotonic increasing.
6851F_ch03_38_63
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3
3.1 (a) Time spent studying is explanatory; the grade is the response variable. (b) Explore the relationship; there is no reason to view one or the other as explanatory. (c) Rainfall is explanatory; crop
yiel
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2
2.1 There are many correct drawings. Here are two possibilities:
(a)
(b)
2.2 (a) The area under the curve is a rectangle with height 1 and width 1. Thus the total area under
the curve 1 1 1.
(b) 20%. (The reg
6851F_ch01_01_25
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1
1.1 (a) The individuals are vehicles (or cars). (b) The variables are: vehicle type (categorical),
transmission type (categorical), number of cylinders (quantitative), city MPG (quantitative), and
highway MPG