According to the growth chart that doctors use as a reference, the heights of two-year-old boys are

Question:

According to the growth chart that doctors use as a reference, the heights of two-year-old boys are normally distributed with mean 34.5 inches and standard deviation 1.3 inches. For a random sample of 6 two-year-old boys, find the probability that the sample mean is between 34.1 and 35.2 inches.