An engineer measured the Brinell hardness of 25 pieces of ductile iron that were sub-critically annealed....

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An engineer measured the Brinell hardness of 25 pieces of ductile iron that were sub-critically annealed. The resulting data were: 170 156 183 156 187 167 163 179 187 167 174 156 174 179 159 179 187 179 183 170 179 156 170 174 179 The engineer wanted to check if the mean Brinell hardness of all such ductile iron pieces is greater than 170. The data can be assumed to normal with standard deviation of 10. Conduct the appropriate test of hypothesis, at significance level of 1% to test of the hardness is greater than 170. An engineer measured the Brinell hardness of 25 pieces of ductile iron that were sub-critically annealed. The resulting data were: 170 156 183 156 187 167 163 179 187 167 174 156 174 179 159 179 187 179 183 170 179 156 170 174 179 The engineer wanted to check if the mean Brinell hardness of all such ductile iron pieces is greater than 170. The data can be assumed to normal with standard deviation of 10. Conduct the appropriate test of hypothesis, at significance level of 1% to test of the hardness is greater than 170.

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To test the engineers hypothesis we can perform a onesample ttest The null hypothesis is that the ... View the full answer