Assume that a normal distribution of data has a mean of 17 and a standard deviation of 5. Use the 68-95-99.7 rule to find the percentage of values that lie above 2. What % of values lie above 2?

Answer 1

To solve this problem, note that 17-2=15, which is 3 standard deviations. The 68-95-99.7 rule states that 99.7% of the population will lie within 3 standard deviations of the mean; this means in this case that 99.7% lie between 2 and 17+15 = 32. Half of the remainder will be below 2, and the other half will be above 32. That means that (100%-99.7%) / 2 = 0.3%/2 = 0.15% will be below 2.