Question

The probability of a student scoring 75% in class work is 0.64, and the probability of a student scoring 85% is 0.45.

Event A: The student scores 75%.
Event B: The student scores 85%.

The probability of a student scoring 85% in class work, given that they have already scored 75% in class work, is 0.55. The probability of a student scoring 75% in class work, given that they have already scored 85% in class work, is 1.
Which statement is true?

Answer 1

Events A and B are independent because P(A|B) = P(A).
Events A and B are independent because P(A|B) = P(B).
Events A and B are independent because P(A|B) = P(A) + P(B).
Events A and B are not independent because P(A| B) ≠ P(A).
Events A and B are not independent because P(A|B) = P(A).

Answer 2

your material should define independence for you. what is that definition?

Answer 3

Oh I forgot to say that I think it's E

Answer 4

if P(A|B) = P(A|U) then we have independance since the amount of A in B is the same ratio as the amount of A in the universal set

Answer 5

So I'm worng

Answer 6

The probability of a student scoring 75% in class work is 0.64,
P(A|U), pr just P(A)

and the probability of a student scoring 85% is 0.45.
P(B|U), or simply P(B)


Event A: The student scores 75%.
Event B: The student scores 85%.

The probability of a student scoring 85% in class work,
given that they have already scored 75% in class work,
is 0.55. P(A|B)

The probability of a student scoring 75% in class work,
given that they have already scored 85% in class work,
is 1. P(B|A)

Answer 7

i see no independence for anything ...

P(A|B) not equal P(A)
P(B|A) not equal P(B)