I want to know how high and how low my electric bill will be. The average is $72.
There is absolutely no way to know. Simply having the average doesn't tell us anything about individual months' usage. You might go on vacation for a month and have a bill that is as low as $10. You might binge on home re-modeling one month and drive your electric bill to $180. An average is just that, a calculated amount. It can come from a huge range of values that no-one can guess.