In the Dorben Company, the work measurement analyst took a detailed time study of the making of shell molds. The third element of this study had the greatest variation in time.After studying nine cycles, the analyst computed the mean and standard deviation of this element, with the following results: 0 = 0.42 s = 0.08. If the analyst wanted to be 90 percent confident that the mean time of her sample was within ±10 percent of the mean of the population, how many total observations should she have taken? Within what percent of the average of the total population is 0 at the 95 percent confidence level under the measured observations?