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20. A tellet at a dribeep windoe at a bark had the following service times (iti minutet) for 20 randemily iefected tuateorer. 4. Deirrnuine the mean of each sumple. b. If the peocess parameten are unknown, tatimate its mesn and standasd deviation. c. Eatimate the mean and atandard deviation of the sampline dutribusion. d. What would threesigma coattol limits for the process be? What alpta riak would they providet c. What alphe risk would coatrot limits of 4.14 and 4.56 provide? 6. Uhing limits of 4.14 and 4.86, are any sample means begood the control limits? If sa which ond.19? h. Explain wty the centrol limist are differest for meant in parts d asd g. chart? Are amy sample means beyond the ceatrol timies? If so, which one(a)