Sonya F. answered • 01/15/15
Tutor
New to Wyzant
Reading, Writing, Public Speaking, Accounting, and Computer
Hi, Alli. There are different ways to calculate "average." Below, I demonstrate two of the most common: mean and median. Questions which ask for "average" are typically asking you to find the arithmetic mean.
Find the Mean
Step 1: Find the sum of the test scores by adding them.
Step 2: Since there are four test scores, divide the sum from Step 1 by 4.
To illustrate, let's assume you carried the following amounts of cash in your wallet: $125 on Monday, $110 on Tuesday, $100 on Wednesday, and $95 on Thursday. How much cash did you carry on average? First, find the sum: $125 + $110 + $100 + $95 = $430. Second, divide the sum of $430 by 4 days: $430/4 = $107.50. This indicates you had $107.50 (give or take a few dollars) in your wallet during that four-day time period.
Find the Median
Just in case you are asked to find the median, here are the steps:
Step 1: Re-order the test scores from low to high.
Step 2: If you have an odd number of test scores (say, 5), the median would literally be the number in the middle. Since you have an even number of test scores [4], the arithmetic mean of the two middle numbers will provide you the median.
To illustrate, let's use the same $125, $110, $100, and $95 from the first example. When we list these amounts from lowest to highest, we get $95 [lowest], $100, $110, and $125 [highest]. There are four dollar amounts - an even number. This means we find the sum of the two middle numbers and divide by 2: (a) The sum of $100 + $110 is $210; (b) $210 divided by 2 = $105.00. Even though we found the median by calculating the arithmetic mean of the middle two numbers [$100 and $110], the median and mean of the four numbers differ because the median only takes the two middle numbers into account.
I hope this helps, Alli!
