A quality control manager at a manufacturing facility has taken four samples with four observations each of the diameter of a part. (a) Compute the mean of each sample. (Round answers to 3 decimal places, e.g. 15.250.) Mean of sample 1 Mean of sample 2 Mean of sample 3 Cean of sample 4 (b) Compute an estimate of the mean and standard deviation of the sampling distribution. (Round answers to 4 decimal places, e.g. 15.2500.) (c) Develop control limits for 3 standard deviations of the product diameter. (Round answers to 2 decimal places, e.s. 15.25.)