Tip:
Highlight text to annotate it
X
- GIVING A TEST TO A GROUP OF STUDENTS,
THE GRADES AND GENDER ARE SUMMARIZED BELOW.
IF ONE STUDENT IS CHOSEN AT RANDOM,
FIND THE PROBABILITY THAT THE STUDENT WAS FEMALE
AND GOT AN "A."
SO LOOKING AT OUR PROBABILITY FORMULA HERE BELOW,
THE TOTAL NUMBER OF OUTCOMES
WOULD BE THE TOTAL NUMBER OF STUDENTS THAT TOOK THE TEST
WHICH WE CAN SEE FROM THE TOTAL COLUMN IS 64.
THE FAVORABLE NUMBER OF OUTCOMES
WOULD BE THE NUMBER OF FEMALE STUDENTS
THAT ALSO RECEIVED AN "A,"
SO LOOKING AT THIS ROW HERE THAT INDICATES
THE NUMBER OF FEMALES THAT TOOK THE TEST,
NOTICE THERE WERE 8 FEMALES.
THEREFORE, THE PROBABILITY OF SELECTING ONE STUDENT
AND THAT ONE STUDENT BEING A FEMALE THAT GOT AN "A,"
SO WE'LL SAY THE PROBABILITY OF A FEMALE WITH AN "A"
WOULD BE EQUAL TO 8.
THE NUMBER OF FEMALE STUDENTS THAT RECEIVED AN "A"
DIVIDED BY THE TOTAL NUMBER OF STUDENTS TAKING THE TEST
WHICH IS 64, 8 AND 64 DO SHARE A COMMON FACTOR OF 8,
SO OUR PROBABILITY = 1/8.
LET'S ALSO EXPRESS THIS AS A DECIMAL AND A PERCENTAGE.
TO CONVERT A FRACTION TO A DECIMAL WE DIVIDE.
1 DIVIDED BY 8 = 0.125.
TO CONVERT TO A PERCENTAGE, WE MULTIPLY BY 100
AND ADD A PERCENT,
OR WE CAN MOVE THE DECIMAL POINT TO THE RIGHT TWO PLACES
GIVING US 12.5%.
I BELIEVE IN OUR HOMEWORK THEY DO WANT
THE PROBABILITY AS A FRACTION OR DECIMAL BUT NOT AS A PERCENT.
I HOPE YOU FOUND THIS HELPFUL.