Final answer:
The formula for the mean water bill for the entire year is the sum of the monthly bills divided by 12 (Σ (monthly bills) / 12). You calculate it by adding all monthly bills and then dividing by 12 to get the average bill for the year, rounded to the nearest cent.
Step-by-step explanation:
To calculate the mean water bill for an entire year using sigma notation, the formula we need is the sum of the monthly bills divided by the number of months in a year. Since there are 12 months in a year, the correct formula to use would be:
Σ (monthly bills) / 12
To determine the mean water bill, first add up all the individual monthly water bills. This is the summation (Σ) part of the formula. Once you have the total, divide this sum by 12 to find the mean (average) monthly water bill. If you round this answer to the nearest cent, you will get the mean monthly water bill for the entire year.