based on records kept at a gas station, the distribution of gallons of gas purchased by customers is skewed to the right with mean 10 gallons and standard deviation 4 gallons. a random sample of 64 customer receipts was selected, and the sample mean number of gallons was recorded. suppose the process of selecting a random sample of 64 receipts and recording the sample mean number of gallons was repeated for a total of 100 samples. which of the following is the best description of a dotplot created from the 100 sample means?