Elementary Statistics - Central Limit Theorem Worksheet The average cost of college for one year is $26,489 with a standard deviation of $3204. If 36 colleges are selected at random, find the following probabilities. 1. Find the probability that the sample mean cost for the 36 schools is less than $25,000. 2. Find the probability that the sample mean cost for the 36 schools is more than $26,000. 3. Find the probability that the sample mean cost for the 36 schools is between $24,000 and $26,000. Chapter 6 - Normal Distribution @Ashley Spencer, 2015\fThe average secretary salary in Ohio is $57,337. Suppose that the distribution of salaries is normal with a standard deviation of $7500. Find the following probabilities. 7. What is the probability that a randomly selected secretary makes less than $52,000 per year? 8. For a sample of 100 secretaries, what is the probability that the sample mean is less than $56,000 per year? Chapter 6 - Normal Distribution