Let’s say you have 5 people take an aptitude test and the maximum possible score is 100. The mean score is calculated by taking the sum of all the data values and dividing it by the total number who took the test. In other words, you add all the scores together and then divide the total by the number of scores (in this case, 5):
56 + 75 + 94 + 82 + 67 = 374
374/5 = 74.8
Therefore, in this case, the mean score is 74.8.