Discussion:
Q: The breaking strengths of cables produced by a certain manufacturer have a mean of 1750 pounds, and a standard deviation of 60 pounds. It is claimed that an improvement in the manufacturing process has increased the mean breaking strength. To evaluate this claim, 80 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1752 pounds. Can we support, at the .05 level of significance, the claim that the mean breaking strength has increased? (Assume that the standard deviation has not changed.)
Perform a one-tailed test.
1. Null hypothesis
2 Hypothesis
3. Type of statistic z t chi f
4. Value of test statistic
5. The p-value
6. Can we support that the mean breaking strength has increased.