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- WELCOME TO AN EXAMPLE OF A GRADE CALCULATION
WITH WEIGHTED AVERAGES.
LET'S ASSUME YOUR GRADE IN MATH CLASS
IS BASED UPON THE FOLLOWING CATEGORIES
WITH THE GIVEN WEIGHTS LISTED HERE ON THE LEFT.
SO IN YOUR CLASS HOMEWORK, ITS WORTH 20% OF THE GRADE,
THE PROJECT IS WORTH 10% OF THE GRADE,
THE TEST ARE WORTH 40% OF THE GRADE,
AND THE FINAL EXAM IS WORTH 30% OF THE GRADE.
NOTICE HOW THIS TOTAL WOULD BE 100% OF YOUR GRADE.
WE WANT TO DETERMINE WHAT IS YOUR GRADE
WITH THE GIVEN PERCENTAGE IN EACH CATEGORY
LISTED HERE ON THE LEFT.
SO YOU'VE EARNED AN AVERAGE OF 96% ON THE HOMEWORK,
85% ON THE PROJECT, 84% ON THE TEST,
AND 92% ON THE FINAL EXAM.
SO TO PERFORM THE WEIGHTED AVERAGE,
WE FIRST WANT TO CONVERT ALL THE PERCENTAGES
FOR EACH CATEGORY INTO A DECIMAL.
REMEMBER TO CONVERT A DECIMAL TO A DECIMAL,
WE'D DROP THE PERCENT SYMBOL AND DIVIDE BY 100.
SO 20% IS EQUAL TO 0.2 OR 2/10,
10% IS EQUAL TO 0.1 OR 1/10,
40% IS EQUAL TO 0.4 OR 4/10,
AND 30% IS EQUAL TO 0.3 OR 3/10.
SO WHAT THIS IS TELLING US
IS LOOKING AT THE HOMEWORK AVERAGE OF 96%
THIS IS WORTH 2/10 OF THE SEMESTER GRADE.
THE PROJECT GRADE OF 85% IS WORTH 1/10
OF THE SEMESTER GRADE.
THE TEST AVERAGE OF 84% IS WORTH 4/10
OF THE SEMESTER GRADE AND SO-ON.
SO TO FIND THE GRADE FOR THE COURSE
USING THESE WEIGHTED AVERAGES,
THE GRADE WILL BE EQUAL TO THE HOMEWORK PERCENTAGE,
WHICH IS 96%.
WE'LL LEAVE OUT THE PERCENT FOR THE CALCULATION,
TIMES THE WEIGHT OF 0.2 + THE PERCENT FOR THE PROJECT,
WHICH IS 85% x THE WEIGHT OF 1/10 OR 0.1
+ THE TEST AVERAGE OF 84% x THE WEIGHT OF 0.4 OR 4/10
+ THE FINAL EXAM GRADE OF 92% x THE WEIGHT OF 30% OR 0.3.
SO THE SUM OF THESE PRODUCTS WILL GIVE US THE GRADE
FOR THE COURSE.
SO WE HAVE 96 x 0.2 + 85 x 0.1 + 84 x 0.4,
AND FINALLY + 92 x 0.3.
THIS COMES OUT TO 88.9,
AND THIS WOULD BE THE PERCENT FOR THE COURSE.
SO LOOKING AT THE GRADE SCALE BELOW,
THIS PROBABLY ISN'T QUITE WHAT YOU WERE HOPING FOR,
NOTICE THE RANGE FOR B IS 79.5% TO 89.4%.
THEREFORE, YOUR COURSE GRADE WOULD BE A B,
EVEN THOUGH IT IS A HIGH B.
I HOPE YOU FOUND THIS EXPLANATION HELPFUL.