...butter manufacturing industry is concerned about the fat content of a certain grade of butter. The manager submits 12 butter samples in the lab for analysis. The percentage of fat in each... Discussion 5 Discussion 5 Example A manufacturer measured the hardness of 25 pieces of an alloy of steel that were sub-critically manufactured, and attained the following data; 167, 163, 179, 187, 167,174, 156,174, 179,159,179, 156,170,174,179,170,156,183,156,187. The manufacturer sets a hypothesis that the mean hardness of all such pieces is greater than 170.
Null hypothesis, H0:µ=170
Alternative hypothesis, H1::µ> 170
The mean hardness = 172.5
Standard deviation can be evaluated to be 10.31
The Test stat...