Use a statistical software package to construct a normal probability plot of the tensile ultimate-strength data given in Exercise 13 of Chapter 1, and comment.
13. Allowable mechanical properties for structural design of metallic aerospace vehicles requires an approved method for statistically analyzing empirical test data. The article “Establishing Mechanical Property Allowable for Metals’’ (J. of Testing and Evaluation, 1998: 293-299) used the accompanying data on tensile ultimate strength (ksi) as a basis for addressing the difficulties in developing such a method.
122.2 | 124.2 | 124.3 | 125.6 | 126.3 | 126.5 | 126.5 | 127.2 | 127.3 |
127.5 | 127.9 | 128.6 | 128.8 | 129.0 | 129.2 | 129.4 | 129.6 | 130.2 |
130.4 | 130.8 | 131.3 | 131.4 | 131.4 | 131.5 | 131.6 | 131.6 | 131.8 |
131.8 | 132.3 | 132.4 | 132.4 | 132.5 | 132.5 | 132.5 | 132.5 | 132.6 |
132.7 | 132.9 | 133.0 | 133.1 | 133.1 | 133.1 | 133.1 | 133.2 | 133.2 |
133.2 | 133.3 | 133.3 | 133.5 | 133.5 | 133.5 | 133.8 | 133.9 | 134.0 |
134.0 | 134.0 | 134.0 | 134.1 | 134.2 | 134.3 | 134.4 | 134.4 | 134.6 |
134.7 | 134.7 | 134.7 | 134.8 | 134.8 | 134.8 | 134.9 | 134.9 | 135.2 |
135.2 | 135.2 | 135.3 | 135.3 | 135.4 | 135.5 | 135.5 | 135.6 | 135.6 |
135.7 | 135.8 | 135.8 | 135.8 | 135.8 | 135.8 | 135.9 | 135.9 | 135.9 |
135.9 | 136.0 | 136.0 | 136.1 | 136.2 | 136.2 | 136.3 | 136.4 | 136.4 |
136.6 | 136.8 | 136.9 | 136.9 | 137.0 | 137.1 | 137.2 | 137.6 | 137.6 |
137.8 | 137.8 | 137.8 | 137.9 | 137.9 | 138.2 | 138.2 | 138.3 | 138.3 |
138.4 | 138.4 | 138.4 | 138.5 | 138.5 | 138.6 | 138.7 | 138.7 | 139.0 |
139.1 | 139.5 | 139.6 | 139.8 | 139.8 | 140.0 | 140.0 | 140.7 | 140.7 |
140.9 | 140.9 | 141.2 | 141.4 | 141.5 | 141.6 | 142.9 | 143.4 | 143.5 |
143.6 | 143.8 | 143.8 | 143.9 | 144.1 | 144.5 | 144.5 | 147.7 | 147.7 |
a. Construct a stem-and-leaf display of the data by first deleting (truncating) the tenths digit and then repeating each stem value five times (once for leaves 1 and 2, a second time for leaves 3 and 4, etc.). Why is it relatively easy to identify a representative strength value?
b. Construct a histogram using equal-width classes with the first class having a lower limit of 122 and an upper limit of 124. Then comment on any interesting features of the histogram.
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Probability and Statistics for Engineering and the Sciences
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