If you wanted to compute for your budget for natural gas
this month using the data you have recorded about your consumption of natural gas
for the past four months, the best estimate to be budgeted this month would be
the average consumption for the past 4 months. To get the average, you have to
add the four numbers and divide it by four.
$112
+ $108 + $99 + $89 = $408/4 = $102
