Ingeniero

Solutions Manual
to accompany

STATISTICS FOR ENGINEERS AND
SCIENTISTS
by

William Navidi

Table of Contents

Chapter 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Chapter 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Chapter 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Chapter 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 115
Chapter 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Chapter 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
Chapter 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 190
Chapter 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Chapter 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

1

SECTION 1.1

Chapter 1
Section 1.1
1. (a) The population consists of all the bolts in theshipment. It is tangible.
(b) The population consists of all measurements that could be made on that resistor with that ohmmeter.
It is conceptual.
(c) The population consists of all residents of the town. It is tangible.
(d) The population consists of all welds that could be made by that process. It is conceptual.
(e) The population consists of all parts manufactured that day. It is tangible.3. (a) False
(b) True

5. (a) No. What is important is the population proportion of defectives; the sample proportion is only an approximation. The population proportion for the new process may in fact be greater or less than that of the old
process.
(b) No. The population proportion for the new process may be 0.10 or more, even though the sample proportion
was only 0.09.
(c) Finding 2defective bottles in the sample.

7.

A good knowledge of the process that generated the data.

2

CHAPTER 1

Section 1.2
1.

False

3.

No. In the sample 1, 2, 4 the mean is 7/3, which does not appear at all.

5.

The sample size can be any odd number.

7.

Yes. If all the numbers in the list are the same, the standard deviation will equal 0.

9.

The mean andstandard deviation both increase by 5%.

 

The total number of points scored in the class of 30 students is 30 72 2160. The total number of points
scored in the class of 40 students is 40 79 3160. The total number of points scored in both classes combined
is 2160 3160 5320. There are 30 40 70 students in both classes combined. Therefore the mean score
for the two classes combined is 5320 70 76.¡

11.

 

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13. (a) All would be multiplied by 2.54.

(b) Not exactly the same, because the measurements would be a little different the second time.

15. (a) The sample size is n 16. The tertiles have cutpoints 1 3 17
5 67 and 2 3 17
11 33. The first tertile
is therefore the average of the sample values in positions 5 and 6, which is 44 46 2 45. Thesecond tertile
is the average of the sample values in positions 11 and 12, which is 76 79 2 77 5.
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(b) The sample size is n 16. The quintiles have cutpoints i 5 17 for i 1 2 3 4. The quintiles are therefore
the averages of the sample values in positions 3 and 4, in positions 6 and 7,...