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- WELCOME TO AN EXAMPLE THAT WE'LL SHOW HOW TO USE
A T84 GRAPHING CALCULATOR TO DETERMINE
HOW A FINAL EXAM SCORE WILL AFFECT A COURSE GRADE
WHEN THE COURSE GRADE IS BASE UPON WEIGHTED AVERAGES.
LET'S ASSUME YOUR COURSE GRADES AND CATEGORY WEIGHTS
ARE SHOWN BELOW.
FOR EXAMPLE, IN THE HOMEWORK CATEGORY, YOU HAVE 93%
AND THIS CATEGORY IS WEIGHTED 20%.
YOUR PROJECT GRADE IS 88%,
WHICH IS WEIGHTED 10% OF YOUR SEMESTER GRADE OR COURSE GRADE.
YOUR TEST AVERAGE IS 86%,
WHICH IS WEIGHTED 40% OF YOUR COURSE GRADE.
AND THEN FINALLY THE UNKNOWN IS THE FINAL EXAM SCORE
OR FINAL EXAM PERCENTAGE,
WHICH WE'LL GO AHEAD AND CALL X,
WHICH IS WEIGHTED 30% OF YOUR SEMESTER GRADE.
SO OUR GOAL HERE IS TO DETERMINE WHAT VALUE OF X
WE HAVE TO SCORE IN ORDER TO HAVE AN "A" GRADE,
WHERE THE LOWEST "A" IS 89.5%.
AND WE'LL LET Y = THE COURSE THE GRADE AS A PERCENTAGE.
SO WE'RE GOING TO SET UP AN EQUATION
USING WEIGHTED AVERAGES,
AND THEN USE THE CALCULATOR TO DETERMINE WHAT X VALUE
WE NEED IN ORDER TO HAVE A Y VALUE THAT'S AT LEAST 89.5%
RESULTING IN AN A.
SO OUR EQUATION IS GOING TO BE Y,
THE SEMESTER GRADE OR COURSE GRADE,
WILL BE EQUAL TO THE HOMEWORK PERCENTAGE TIMES THE WEIGHT.
THE HOMEWORK PERCENT IS 93%.
WE'LL JUST USE 93 x THE WEIGHT OF 20%,
EXPRESSED AS A DECIMAL IT WOULD BE 0.2 + THE PROJECT PERCENTAGE,
WHICH IS 88 x THE WEIGHT OF 10%,
AS A DECIMAL 0.1 + THE TEST AVERAGE OF 86%
x THE WEIGHT OF 40% OR 0.4 AS A DECIMAL.
FINALLY PLUS THE FINAL EXAM SCORE,
WHICH IS THE UNKNOWN X x THE WEIGHT OF 30% OR 0.3.
SO, AGAIN, THE IMPORTANT THING TO RECOGNIZE HERE IS THAT X
IS THE FINAL EXAM PERCENTAGE,
AND Y IS THE COURSE GRADE AS A PERCENTAGE.
SO NOW WE'LL ENTER THIS EQUATION INTO THE GRAPHING CALCULATOR.
SO WE'RE GOING TO PRESS Y EQUALS,
CLEAR OUT ANY OLD EQUATIONS.
SO, CLEAR, ENTER, CLEAR, BACK UP TO Y1.
WE'LL ENTER THE RIGHT SIDE OF THIS EQUATION JUST AS IT LOOKS.
SO 93 x 0.2 + 88 x 0.1 + 86 x 0.4, THEN FINALLY + X x 0.3.
SO, AGAIN, X WILL BE THE FINAL EXAM PERCENTAGE
AND Y WILL BE THE COURSE PERCENTAGE.
SO NOW WE'RE GOING TO USE A TABLE FEATURE
TO ANSWER THIS QUESTION,
BUT BEFORE WE DO THAT LETS CHECK OUR TABLE SET
BY PRESSING "SECOND WINDOW."
LET'S HAVE THE TABLE START AT 50.
THIS WILL BE A FINAL EXAM SCORE TO 50%.
AND WE'LL HAVE THE CHANGING TABLE HERE BE EQUAL TO 1 FOR 1%.
NOW WE'LL GO TO THE TABLE BY PRESSING "SECOND GRAPH."
SO, AGAIN, X REPRESENTS THE FINAL EXAM PERCENTAGE,
AND Y REPRESENTS THE COURSE PERCENTAGE.
AS WE SCROLL THROUGH THIS TABLE,
WE CAN SEE HOW ANY FINAL EXAM PERCENTAGE
WILL AFFECT THE COURSE PERCENTAGE.
SO WE'LL GO AHEAD AND SCROLL UP.
NOTICE AS THE FINAL EXAM PERCENTAGE INCREASES,
SO DOES THE COURSE PERCENTAGE.
WE CAN SEE HERE THAT THE LOWEST B,
WHICH 79.5% WOULD OCCUR IF YOU SCORED 59% ON THE FINAL EXAM.
BUT OF COURSE YOU'LL DO MUCH BETTER THAN THAT.
LET'S SEE HOW WE HAVE TO SCORE IN ORDER TO RECEIVE AN A.
SO WE'RE LOOKING FOR A Y VALUE THAT'S AT LEAST 89.5.
NOTICE HOW IT WOULD TAKE A 93%,
92% IS NOT HIGH ENOUGH BECAUSE THAT RESULTS IN 89.4,
WHICH IS STILL A B.
SO OUR ANSWER WOULD BE YOU HAVE TO SCORE 93% ON THE FINAL EXAM
TO RECEIVE AN A.
SO THE CONCLUSION IS YOU MUST SCORE AT LEAST 93% ON THE FINAL
TO RECEIVE AN "A" ON THE COURSE.
WHICH I'M SURE YOU WILL DO.
I HOPE YOU FOUND THIS EXPLANATION HELPFUL.