A survey of teenagers' allowances showed a normal distribution with mean $20 and a standard deviation of $2. What is the probability that a student's allowance would fall between $18 and $22?

Question

kropot72 · Answer

The empirical rule in statistics states that for all normal distributions approximately 68% of the data points lie within the range plus and minus 1 standard deviation from the mean. In this case $22 and $18 lie within the range plus and minus 1 standard deviation from the mean of $20.