1. The following data are the numbers of cycles to failure of aluminium test coupons subjected to repeated alternating stress at 21,000 psi, 18 cycles per second. 1115 865 1015 885 1594 1000 1416 1501 1310 2130 845 1223 2023 1820 1560 1238 1540 1421 1674 375 1315 1940 1055 990 1502 1109 1016 2265 1269 1120 1764 1468 1258 1481 1102 1910 1260 910 1330 1512 1315 1567 1605 1018 1888 1730 1608 1750 1085 1883 706 1452 1782 1102 1535 1642 Construct a stem-and-leaf display for these data.

10.1.4 A polymer is manufactured in a batch chemical process. Viscosity measurements are normally made on each batch, and long experience with the process has indicated that the variability in the process is fairly stable with o = 20. Fifteen batch viscosity measurements are given as follows: 724, 718, 776, 760, 745, 759, 795, 756, 742, 740, 761, 749, 739, 747, 742 A process change that involves switching the type of catalyst used in the process is made. Following the process change, eight batch viscosity measurements are taken: 735, 775, 729, 755, 783, 760, 738, 780 Assume that process variability is unaffected by the catalyst change. If the difference in mean batch viscosity is 10 or less, the manufacturer would like to detect it with a high probability. a. Formulate and test an appropriate hypothesis using α = 0.10. What are your conclusions? Find the P-value. b. Find a 90% confidence interval on the difference in mean batch viscosity resulting from the process change. c. Compare…

Much concern has been expressed regarding the practice of using nitrates as meat preservatives. In one study involving possible effects of these chemicals, bacteria cultures were grown in a medium containing nitrates. The rate of uptake of radio-labeled amino acid (in dpm, disintegrations per minute) was then determined for each culture, yielding the following observations. 7,256 6,876 9,634 6,867 9,091 5,848 7,061 7,491 7,882 8,173 7,521 8,721 8,959 7,973 X 7,463 Suppose that it is known that the mean rate of uptake for cultures without nitrates is 8,000. Do the data suggest that the addition of nitrates results in a decrease in the mean rate of uptake? Test the appropriate hypotheses using a significance level of 0.10. Find the test statistic and P-value. (Use technology to calculate the P-value. Round your test statistic to two decimal places and your P-value to four decimal places.) t = P-value = 0.2142 State your conclusion. O Fail to reject Ho. We have convincing evidence that…

Much concern has been expressed regarding the practice of using nitrates as meat preservatives. In one study involving possible effects of these chemicals, bacteria cultures were grown in a medium containing nitrates. The rate of uptake of radio-labeled amino acid (in dpm, disintegrations per minute) was then determined for each culture, yielding the following observations. 7,255 6,875 9,637 6,863 9,098 5,846 8,954 7,979 7,068 7,498 7,882 8,179 7,528 8,728 7,469 Suppose that it is known that the mean rate of uptake for cultures without nitrates is 8,000. Do the data suggest that the addition of nitrates results in a decrease in the mean rate of uptake? Test the appropriate hypotheses using a significance level of 0.10. Find the test statistic and P-value. (Use technology to calculate the P-value. Round your test statistic to two decimal places and your P-value to three decimal places.) t= P-value= State your conclusion. Reject H0. We have convincing evidence that the mean rate of…

c)

Listed below are amounts of strontium-90 (in millibecquerels, or mBq) in a simple random sample of baby teeth obtained from residents in a region born after 1979. Use the given data to construct a boxplot and identify the 5-number summary. 122 141 123 142 125 144 130 147 131 149 i 133 154 *** The 5-number summary is 122, 131.5, 140, 152.75, and (Use ascending order. Type integers or decimals. Do not round.) S √₁ 133 156 all in mBq. Vi I, 135 158 (,) 137 161 More 139 168

A worker with a weight of 65 kg and a body surface area of 1.74 , performs physical work activities in several work environments as shown in the following table. The work activities of these workers require energy and a measured metabolic rate of 400 W/m2. During their work activities, the worker wears a coverall made of polyolefin and wears a headgear (1) Calculate the average WBGT of the work environment. (2) Perform an analysis related to the heat stress experienced by the worker, if the worker performs his work activities for 75% of his total working time and the rest is rest, (note: use TLV from ACGIH and ISO 7243)