Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

650 Chapter 19 Probability and Statistics in Engineering

In closing, keep in mind that the purpose of this chapter was to make you aware of the

importance of probability and statistics in engineering, not to provide a detailed coverage of sta-

tistics. As you take statistics classes and advanced classes in engineering, you will learn much

more about statistical concepts and models.

Summary

Now that you have reached this point in the text

• You should understand the important role of statistics in various engineering disciplines.


• You should be familiar with basic probability and statistics terminologies.


• You should have a good understanding of frequency distribution and cumulative frequency
  distribution and what kind of information they provide.


• You should have a good grasp of statistical measures of central tendency and variation.


• You should know how to compute basic statistical information such as mean, variance, and
  standard deviation for a set of data points.


• You should know what is meant by normal distribution and standard normal distribution.


• You should know how to use Table 19.11.

Problems

z  0.34

A  0.1331

A  0.3669

■Figure 19.9

Areas under the probability distribution curve for Example 19.7.

19.1. The scores of a test for an engineering class of

30 students is shown here. Organize the data in a man-

ner similar to Table 19.1 and use Excel to create a

histogram.

Scores:57, 94, 81, 77, 66, 97, 62, 86, 75, 87, 91, 78,

61, 82, 74, 72, 70, 88, 66, 75, 55, 66, 58, 73, 79,

51, 63, 77, 52, 84

19.2. For Problem 19.1, calculate the cumulative frequency

and plot a cumulative-frequency polygon.

19.3. For Problem 19.1, using Equations (19.1) and (19.6),

calculate the mean and standard deviation of the class

scores.

19.4. For Problem 19.1, using Equations (19.7) and (19.8),

calculate the mean and standard deviation of the class

scores.

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