QUESTlDN 1: a. A random sample 40 light bulbs produced by an electric rm lasted an average 1356 hours widt standard deviation 13G hours Construct 85% confidence interval ofthe average life of all light bulbs manufactured by the rm, if the lives fol low normal distribution. b. A certain type of seed has always grows to a mean height of 8.5 inches. A sample of 15D seeds grown under new condition has a mean height ofBB inches and a standard deviation of 1 inch. At the 1% of significance level, test the hypothesis that the new conditions grow better plar'ris r. A study was made to estimate the difference in life of bulb used in floor lamps used in photograph}.f produced by manufacturers A and E. A random sample of size 12 is taken from the bulbs manufactured by A and the mean life was found to be 520 hours with a standard deviation of 55 hours Amtt'ier random sample of size 13 is taken from the bulbs manufactured by B and the mean life was found to be 555 hours with standard deviation of in hours Find a 90% condence interval for the difference of the population mean. Assume the populations to be approximatelv normallyr distributed with equal variance d. Consider a population 2 3. 5. I5, and I draw all possible of size lwith replacement 'vien'fv mar a. Exzp b. W252i}