A population of 10,000 students spends an average of $8.50 a day on dinner. The standard deviation of the expenditure is $4. A simple random sample of 100 students is taken. What is the standard deviation of the sampling distribution of the sample mean? Round your answer to 3 decimal places and no dollar sign. Solution As s(X) = s/sqrt(n) Then, as s = 4, n = 100, s(X) = 4/sqrt(100) = 0.4 [ANSWER].