A manufacturing company produces electrical insulators. If theinsulators break when in use, a short circuit is likely to occur.To test the strength of the insulators, destructive testing iscarried out to determine how much force is required to break theinsulators. Force is measured by observing the number of pounds offorce applied to the insulator before it breaks. The data shownbelow are from 30 insulators subjected to this testing:
Force |
1870 |
1728 |
1656 |
1610 |
1634 |
1784 |
1522 |
1696 |
1592 |
1662 |
1866 |
1764 |
1734 |
1662 |
1734 |
1774 |
1550 |
1756 |
1762 |
1866 |
1820 |
1744 |
1788 |
1688 |
1810 |
1752 |
1680 |
1810 |
1652 |
1736 |
- At the 0.05 level of significance, is there evidence that thepopulation mean force required to break the insulator is greaterthan 1,500 pounds?
- What assumption about the population distribution is needed inorder to conduct the t test in (a)?
- Construct a histogram or a boxplot, or a normal probabilityplot to evaluate the assumption made in (b).
- Do you think that the assumption needed in order to conduct thet test in (a) is valid? Explain.
