*Show working out. QUESTION 1: A manager of an e- commerce companv would like to determine average delivery time of the products. A sample of 25 customers is taken. The average delivery time in the sample was four days with a standard deviation of 1.2 days. Suppose the delivery times are normally distributed. i) Estimate the mean delivery with a 80% confidence. il) Estimate the mean delivery with a 98% confidence. ili) Show the trade-off between precision and confidence in this example. QUESTION 2: A car sales company tries to evaluate the performance of each of its more than 200 branches. To do so, it chooses a random sample of 40 branches and obtains their average performance. The average pertormance iS 4.5%. Use this intormation, to build a 68% and 99% confidence interval to estimate the mean performance of all branches, in each case