The standard deviation of the weights of elephants is known to be approximately 15 pounds. We wish to construct a 95% confidence interval for the mean weight of newborn elephant calves. Fifty newborn elephants are weighed. The sample mean is 244 pounds. The sample standard deviation is 11 pounds. In words, define the random variables X and X. X is the weight in pounds of a newborn elephant, and X is the sample mean of the 50 baby elephants. X is the weight in pounds of a newborn elephant, and X is the standard deviation of the weights of baby elephants. X is the average of weights of the sample of 50 newborn elephant, and X is the weight in pounds of a baby elephant. X is the weight in pounds of a newborn elephant, and X is the average of weights of the sample of 50 baby elephants. X is the sample mean of the weights of the sample of 50 newborn elephant, and X is the sample standard deviation of weights of the sample of 50 baby elephants.