A manufacturing company produces electric insulators. You define the variable of interest as the strength of the insulators. If the insulators break when inuse, a short circuit is likely. To test the strength of theinsulators, you carry out destructive testing to determine how much force is required to break the insulators. You measure force by observing how many pounds are applied to the insulator before it breaks. The accompanying data represents the amount of force required to break a sample of 30 insulators. Complete parts (a) through (c) below.

Accompanying data:

1887 1749 1661 1624 1632 1793 1597 1671 1579 1682 1886 1695 1742 1652 1731 1759 1652 1781 1786 1891 1818 1738 1775 1651 1846 1797 1671 1806 1694 1706

A. construct a 99% confidence interval for the population mean force

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b. What assumption must you make about the population distribution in order to construct the confidence interval estimate in(a)?

c. Do you think that the assumption needed in order to construct the confidence interval estimate in(a) isvalid? Explain.