The National Assessment of Educational Progress (NAEP) includes a mathematics test for high school seniors. Scores on the test range from 0 to 300. Suppose that you give the NAEP test to an SRS of 900 12th-graders from a large population in which the scores have unknown mean and standard deviation = 35. The mean score will vary if you take repeated samples.
The sampling distribution of mean score is approximately Normal. It has mean . What is its standard deviation?