The breaking strength of cables has a mean of 1775 lbs and a standard deviation of 80 lbs. An improvement has increased the mean strength. To eval this claim 70 new cables are randomly chosen and tested. their mean breaking strength is found to be 1794 lbs. Can we support at the 0.05 level of significance the claim that the mean breaking strength has increased. Standard deviation remains the same.
- What is the null hypothesis?
- Alternative hypothesis?
- Type of test? Z t F or chi square
- Value of test statistic round to 3 decimal places
- p value rounded to 3 decimal places
- Can we support the claim that strength has increased