Download Unit 7 Extra Practice Answers

Name
Master 7.25
Date
Extra Practice Sample Answers
Extra Practice 1 – Master 7.19
1. a) 7
b) 33
c) 5
d) 14
2. a) 3
b) 45
c) 143, 534
d) No mode
3. a) 57, 56, 36
b) No mode, 17, 10
c) Brown; he has the most hits and has fewer strikeouts than Green.
Extra Practice 2 – Master 7.20
1. a) 75, 45
b) 22.5, 33
c) 105.5, 504
d) 42, 90
2. a) 35
b) 18.5
3. a) For example: 10, 12, 14, 16, 18
b) For example: 7, 8, 9, 10, 14, 22, 23, 24, 25, 26
c) For example: 3, 9, 11, 14, 16, 17, 19, 21
4. a) The 12th number
b) The mean of the 12th and 13th numbers
5. For example, 20, 25, 33, 34, 38 and 19, 24, 33, 33, 41
6. a) For example, the ages in years might be: 18, 18, 19, 23, 31, 34, 34, 37, 39, 45, 53, 60
b) For example, the ages in years might be: 21, 25, 29, 39, 45, 45, 45, 51, 71, 78
Extra Practice 3 – Master 7.21
1. a) Mean: about 67.47, median: 70, mode: 70
b) The outliers are 25, 99, 100.
c) Mean: about 65.9, median: 69.5, mode: 70
The mean and the median decreased slightly. The mode remained the same.
2. a) Mean: $1530, median: $1380, mode: $1250
b) The outliers are $120 and $3500.
Mean: $1450; median: $1380; mode: $1250
Only the mean is affected by the outliers; the median and mode are not affected by the outliers.
c) Answers may vary. I would not include $120. I assumed the employee had been sick. I would include
$3500 because an employee did earn this amount of commission.
3. a) The conclusion is correct because the mode represents the number that occurs most often,
so, in this case, it is the shoe size that is sold most often.
b) The conclusion is incorrect because the mean is the sum of the data values divided by the number of data
values. So there could be more or less than 235 students buying their lunch on a given day.
4. a) Mean: about 41.7, median: 45, mode: 45
b) 0, 90
Mean: 41.4, median: 45, mode: 45
The mean decreased slightly. The median and mode remained the same.
c) Yes, to understand how much time the class is spending doing homework, all times should be included.
Extra Practice 4 – Master 7.22
1. a) Mean: about 215.7 s, median: 215 s, mode: 215 s
b) Any of the measures would best describe the race time because all three are close in value.
c) 11 s
d) 207 s; it would be very difficult because the student would have to beat her or his best time by 4 s.
2. a) [(11  415) + (4  418) + (8  420) + (10  422) + (7  430)]  40
b) Mean: about 420.7 g; Median: 420 g; Mode: 415 g
c) Yes, the mean mass is slightly greater than 420 g.
d) 411 g
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Name
Date
Extra Practice 5 – Master 7.23
9
1. a) 37 , 9:37, about 24%
15
b) 37, 15:37, about 41%
21
16
c) 37 , 21:37, about 57%
d) 37, 16:37, about 43%
2. Answers may vary.
a) Roll a 2 on a tetrahedron labelled 1 to 4.
b) Draw a red counter from a bag that contains a red counter, a green counter, and a blue counter.
c) Roll a number greater than 0 on a die labelled 1 to 6.
d) Roll a number less than 0 on a die labelled 1 to 6.
5
1
3. a) 20 = 4, 1:4, 25%
c)
4. a)
c)
7
b) 20, 7:20, 35%
20 – 8 12 3
20 = 20 = 5, 3:5, 60%
8
1
120 = 15, 1:15, about 7%
70 – 25
45
9
70 = 70 = 14, 9:14, about
9
b) 0, 0%; 85, 9:85, about 11%
64%
Extra Practice 6 – Master 7.24
1. a) Answers may vary. I made orange 6 times in 20 trials.
b) Answers may vary. Sample answer: In 200 trials, orange was made 47 times. The experimental
probability of making orange is
47
200
, or about 24%.
c)
d) There are 16 possible outcomes. There are 4 outcomes that make orange.
The probability of making orange is
4 1

16 4
or 25%.
e) Answers may vary. The experimental probability of making orange is about 24% and the theoretical
probability is 25%. They are very close in value.
2. a)
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Name
Date
b) There are 24 possible outcomes.
i) There are 6 outcomes with two even numbers:
(2, 2), (2, 4), (2, 6), (4, 2), (4, 4), and (4, 6).
The probability of rolling two even numbers is
6 1

24 4
or 25%.
ii) There are 4 outcomes with numbers whose sum is 6: (1, 5), (2, 4), (3, 3), and (4, 2).
The probability of rolling two numbers whose sum is 2 is
4 1

24 6
or about 17%.
iii) There are 9 outcomes with a 4: (1, 4), (2, 4),
(3, 4), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), and
(4, 6). The probability of rolling a 4 is 9 or about 38%.
24
iv) There are 11 outcomes with numbers whose difference is 0 or 1: (1, 1), (1, 2), (2, 1), (2, 2),
(2, 3), ( 3, 2), (3, 3), (3, 4), (4, 3), (4, 4), and (4, 5).
The probability of rolling numbers whose difference is 0 or 1 is
11
24
or about 46%.
3. a) The possible sums are: 4, 5, 6, 7, 8, 9
b) Answers may vary.
Sum
4
Frequency 2
5
2
6
5
7
7
8
4
9
0
c) Answers may vary.
d)
e) There are 12 possible outcomes.
i) There is one outcome with sum 9:
1
12
or about 8%.
ii) There are 5 outcomes with a sum of 6 or 8:
iii) There are 2 outcomes with sum 5:
2 1

12 6
5
12
or about 42%.
or about 17%.
f) Answers may vary. The values of the experimental probabilities are close to those of the theoretical
probabilities. The theoretical and experimental probabilities will become closer in value if the experiment is
repeated 1000 times.
The right to reproduce or modify this page is restricted to purchasing schools.
This page may have been modified from its original. Copyright © 2007 Pearson Education Canada