A manufacturing company produces electric insulators. You define the variable of interest as the strength of the insulators. If the insulators break when in use, a short circuit is likely. To test the strength of the insulators, 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. You collect the force data for 20 insulators selected for the experiment and organize and store these data (force2). (a) Compute the sample mean and sample standard deviation. (b) Assuming that the population standard deviation is known as = 95, construct a 95% confidence interval estimate for the population mean force. (c) Assuming that the population standard deviation is unknown, construct a 95% confidence interval estimate for the population mean force. (d) Comparing the results in (b) and (c), explain the difference. Force 1888 1777 1666 1876 1634 1784 1522 1696 1592 1662 1866 1764 1734 1662 1734 1774 1550 1756 1762 1866