Statistics for Engineers and Scientists
4th Edition
ISBN: 9780073401331
Author: William Navidi Prof.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 1.1, Problem 6E
Refer to Exercise 5. True or false:
- a. If the proportion of defectives in the sample is less than 12%, it is reasonable to conclude that the new process is better.
- b. If the proportion of defectives in the sample is only slightly less than 12%, the difference could well be due entirely to sampling variation, and it is not reasonable to conclude that the new process is better.
- c. If the proportion of defectives in the sample is a lot less than 12%, it is very unlikely that the difference is due entirely to sampling variation, so it is reasonable to conclude that the new process is better.
5. A certain process for manufacturing integrated circuits has been in use for a period of time, and it is known that 12% of the circuits it produces are defective. A new process that is supposed to reduce the proportion of defectives is being tested. In a simple random sample of 100 circuits produced by the new process, 12 were defective.
- a. One of the engineers suggests that the test proves that the new process is no better than the old process, since the proportion of defectives in the sample is the same. Is this conclusion justified? Explain.
- b. Assume that there had been only 11 defective circuits in the sample of 100. Would this have proven that the new process is better? Explain.
- c. Which outcome represents stronger evidence that the new process is better: finding 11 defective circuits in the sample, or finding 2 defective circuits in the sample?
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Question 4
An article in Quality Progress (May 2011, pp. 42-48) describes the use of factorial experiments to improve a
silver powder production process. This product is used in conductive pastes to manufacture a wide variety of
products ranging from silicon wafers to elastic membrane switches. Powder density (g/cm²) and surface area
(cm/g) are the two critical characteristics of this product. The experiments involved three factors: reaction
temperature, ammonium percentage, stirring rate. Each of these factors had two levels, and the design was
replicated twice. The design is shown in Table 3.
A222222222222233
Stir Rate
(RPM)
Ammonium
(%)
Table 3: Silver Powder Experiment from Exercise 13.23
Temperature
(°C)
Density
Surface Area
100
8
14.68
0.40
100
8
15.18
0.43
30
100
8
15.12
0.42
30
100
17.48
0.41
150
7.54
0.69
150
8
6.66
0.67
30
150
8
12.46
0.52
30
150
8
12.62
0.36
100
40
10.95
0.58
100
40
17.68
0.43
30
100
40
12.65
0.57
30
100
40
15.96
0.54
150
40
8.03
0.68
150
40
8.84
0.75
30
150…
Chapter 1 Solutions
Statistics for Engineers and Scientists
Ch. 1.1 - Each of the following processes involves sampling...Ch. 1.1 - If you wanted to estimate the mean height of all...Ch. 1.1 - True or false: a. A simple random sample is...Ch. 1.1 - A sample of 100 college students is selected from...Ch. 1.1 - A certain process for manufacturing integrated...Ch. 1.1 - Refer to Exercise 5. True or false: a. If the...Ch. 1.1 - To determine whether a sample should be treated as...Ch. 1.1 - A medical researcher wants to determine whether...Ch. 1.1 - A medical researcher wants to determine whether...Ch. 1.2 - True or false: For any list of numbers, half of...
Ch. 1.2 - Is the sample mean always the most frequently...Ch. 1.2 - Is the sample mean always equal to one of the...Ch. 1.2 - Is the sample median always equal to one of the...Ch. 1.2 - Find a sample size for which the median will...Ch. 1.2 - For a list of positive numbers, is it possible for...Ch. 1.2 - Is it possible for the standard deviation of a...Ch. 1.2 - In a certain company, every worker received a...Ch. 1.2 - In another company, every worker received a 5%...Ch. 1.2 - A sample of 100 adult women was taken, and each...Ch. 1.2 - In a sample of 20 men, the mean height was 178 cm....Ch. 1.2 - Each of 16 students measured the circumference of...Ch. 1.2 - Refer to Exercise 12. a. If the measurements for...Ch. 1.2 - There are 10 employees in a particular division of...Ch. 1.2 - Quartiles divide a sample into four nearly equal...Ch. 1.2 - In each of the following data sets, tell whether...Ch. 1.3 - The weather in Los Angeles is dry most of the...Ch. 1.3 - Forty-five specimens of a certain type of powder...Ch. 1.3 - Refer to Table 1.2 (in Section 1.2). Construct a...Ch. 1.3 - Following are measurements of soil concentrations...Ch. 1.3 - A certain reaction was run several times using...Ch. 1.3 - Sketch a histogram for which a. The mean is...Ch. 1.3 - The figure below is a histogram showing the...Ch. 1.3 - The histogram below presents the compressive...Ch. 1.3 - Refer to Table 1.4 (in Section 1.3). a. Using the...Ch. 1.3 - Refer to Table 1.5 (in Section 1.3). a. Using the...Ch. 1.3 - The following table presents the number of...Ch. 1.3 - Which of the following statistics cannot be...Ch. 1.3 - A sample of 100 resistors has an average...Ch. 1.3 - Following are boxplots comparing the amount of...Ch. 1.3 - Following are summary statistics for two data...Ch. 1.3 - Match each histogram to the box plot that...Ch. 1.3 - Prob. 17ECh. 1.3 - Match each scatterplot to the statement that best...Ch. 1.3 - Prob. 19ECh. 1 - A vendor converts the weights on the packages she...Ch. 1 - Refer to Exercise 1. The vendor begins using...Ch. 1 - The specification for the pull strength of a wire...Ch. 1 - A coin is tossed twice and comes up heads both...Ch. 1 - The smallest number on a list is changed from 12.9...Ch. 1 - There are 15 numbers on a list, and the smallest...Ch. 1 - There are 15 numbers on a list, and the mean is...Ch. 1 - The article The Selection of Yeast Strains for the...Ch. 1 - Concerning the data represented in the following...Ch. 1 - True or false: In any boxplot, a. The length of...Ch. 1 - For each of the following histograms, determine...Ch. 1 - In the article Occurrence and Distribution of...Ch. 1 - The article Vehicle-Arrival Characteristics at...Ch. 1 - The cumulative frequency and the cumulative...Ch. 1 - The article Hydrogeochemical Characteristics of...Ch. 1 - Water scarcity has traditionally been a major...Ch. 1 - Prob. 18SECh. 1 - The article The Ball-on-Three-Ball Test for...
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