The distribution of weight for the tomatoes at store 1 is approximately normal with mean 110 grams and standard deviation 12 grams. the distribution of weight for tomatoes at store 2 is approximately normal with mean 105 grams and standard deviation of 9 grams. if randome sample of size 4 are selected from each store, what are the mean and standard deviation of the smapling distribuion of the difference in sample mean weight