Weighted mean

MATH

before we begin let's get in some relevant Hebrew vocabulary so that we are advancing our Hebraic education in every circumstance

Weighted Mean
MMu3a7 M5uQLaL ממוצע משוקלל

The weighted mean is used when numbers in a set are not all equally important. Those with more importance are given more weight when calculating the mean, or average. Here's how.

Let's say there are 4 tests in total for a certain class: Exam A, the Midterm Exam, Exam B, and the final Exam. Exam A and B may be worth only 20% each of your final grade, while the Midterm and Final Exams may each be worth 30% of your final grade. You happen to score the following on each:

Exam A-95
Midterm Exam-90
Exam B-92
Final Exam-87

To calculate your final grade for the class, you can't just take the mean (average), since the Midterm and Final exams have more weight than Exams A and B. So you must find the weighted mean. Start by writing the weights next to each corresponding item.

Exam A-95             20%
Midterm Exam-90 30%
Exam B-92              20%
Final Exam-87        30%

Now multiply each score by its weight and write that new value off to the right.

Exam A-95             20% = 1,900
Midterm Exam-90 30% = 2,700
Exam B-92              20& = 1,840
Final Exam-87        30% = 2,610

Add up both the final column and the weights column.

Exam A-95              20% = 1,900
Midterm Exam-90 30% = 2,700
Exam B-92              20& = 1,840
Final Exam-87        30% = 2,610
                                 100%   9,050

Now divide the total value by the total of the weights to get the weighted average.

9050÷100=90.5

Your final grade in class would be 90.5

In summary, you can calculate the weighted mean by following these steps:

STEP 1. Multiply your values by their respective weights
STEP 2. Add all your weights together and all your new values together
STEP 3. Divide the total new value by the total weight.

Not that it's real important but:

For converting percentages into decimals click here
For multiplying decimals click here