Question

Janet wanted to understand whether grade level had any relationship to their opinion on extending the school day. She surveyed some students and displayed the results in the table below:


In favor Opposed Undecided
Grade 9 4 2 8
Grade 10 7 11 8
Grade 11 14 15 9
Grade 12 11 5 10


Compare P(Grade 9 | opposed) with P(opposed | Grade 9).

Answer 1

Answer choices
P(Grade 9 | opposed) = P(opposed | Grade 9)
P(Grade 9 | opposed) > P(opposed | Grade 9)
P(Grade 9 | opposed) < P(opposed | Grade 9)
There is not enough information.

Answer 2

@mathmate

Answer 3

to find
P(Grade 9 | opposed)
that says Given the opposed (so circle that whole column)
how many are Grade 9.
write down the fraction # in Grade 9 in the opposed column
divided by the total number in the opposed column (all Grades)

Answer 4

to find
P(opposed | Grade 9).

which means Given Grade 9 (i.e. circle the Grade 9 row)
how many in that row are opposed?
make the fraction
# in Grade 9 who are opposed
divided by
total number in Grade 9 (add up all the numbers in that row)

Answer 5

so it B @phi

Answer 6

are you able to find
P(Grade 9 | opposed)
?

do you see the opposed column? what is the sum of that column?

Answer 7

33

Answer 8

@phi

Answer 9

and 2 out of the 33 are Grade 9
so the probability of Grade 9 given opposed is 2/33

Answer 10

okay i understand that

Answer 11

now do
P(opposed | Grade 9)
we are "given Grade 9"
what is the sum of numbers in Grade 9 ?

Answer 12

14

Answer 13

and how many of that 14 are "opposed" ?
what is the fraction you should make?

Answer 14

2/14

Answer 15

so now you have
2/33 2/14
which one is bigger ?

Answer 16

2/14

Answer 17

so its c

Answer 18

so you want the relation that has the "big side" next to the 2/14
2/33 < 2/14

Answer 19

yes, choice C

Answer 20

alright thank you so much