The energy consumption levels for single-family homes are found to be normally distributed with a mean of 1050 kWh and a standard deviation of 218 kWh. How do you find the probability that the energy consumption level is between 1100 kWh and 1221 kWh?
Given: normal distribution,
Find the z-scores of each energy level:
Look up the probabilities of each z-score from a z-table:
The probability that the energy level is between these two values is