Question

Brad is testing whether school is more enjoyable when students are making high grades. He asked 110 students if they enjoyed school and whether their GPA was above or below 3.5. He found that 38 of the 45 students with a GPA above 3.5 reported that they enjoyed school, and 7 of the 65 students with a GPA below 3.5 reported that they enjoyed school. What is the probability that a student with a GPA below 3.5 does not enjoy school?
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Answer 1

@mathmale

Answer 2

This, woohoo, is a question involving CONDITIONAL PROBABILITY. What does cond. prob. mean to you, if anything?

Answer 3

conditional probability this is the same question as the previous one i just need some guidance

Answer 4

I view this as pretty much a whole new topic.
Have y ou heard the term "contingency table"? If so, what's a c. t. for?

Answer 5

let me look in my book again

Answer 6

Please look up "contingency table" and "conditional probability"; focus on the part of "conditional probability" that involves "contingency tables."

Answer 7

I cant find anything just hold on im sorry

Answer 8

In the meantime I'm going to begin creating a contingency table for this problem, and will be asking you for help in filling it out.

>3.5 <3.5 totals

enjoy

~enjoy

totals 110

Answer 9

BRB

Answer 10

how do i fill this out? i want to learn but in fast forward mode

Answer 11

The trick here is that we have to extract info from the problem statement and put it into the right boxes in the table. Other boxes we'll have to fill using addition and subtraction.

Answer 12

7/65

Answer 13

Hate to say no, but we really can't determine much from this table until it's pretty much finsihed.

Answer 14

Look at what the problem statement sez: "38 of 45 students with >3.5 GPA report that they enjoy school

Answer 15

"

Answer 16

Think about how you might put that data into the table. I will now copy the table below, so you can get started:
Or at least I was going to copy and paste it; my computer isn't copying for me right now. Can you copy the table and paste it below?

Answer 17

i tried before you told me it wont let me

Answer 18

Darn. In that case I'll try drawing a table instead of copying and pasting. Familiar with the Draw utility?

Answer 19

ill just type it

Answer 20

Look what the problem statement sez: 38 of 45 students with gpa s above 3.5 enjoy school.

Answer 21

total

Answer 22

This tell s us that 45 students have gpa s above 45, right?