SOLUTION: Grade___Students__>8 HRS.__<8 HRS. A_______13_______12_______1 B_______10_______8________2 C_______8________6________2 D_______9________2________7 F_______10_______1____

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Question 917486: Grade___Students__>8 HRS.__<8 HRS.
A_______13_______12_______1
B_______10_______8________2
C_______8________6________2
D_______9________2________7
F_______10_______1________9
What is the probability of a randomly selected student having earned an A on the exam given they devoted no more than 8 hours to studying for the exam?
a. 0.12
b. 0.21
c. 0.17
d. 0.05
I am confuse on how to solve this problem can you please help me out. Thank.
Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website!

Hi
Trouble only because Totals hadn't been filled in:
Grade___Students__>8 HRS.__<8 HRS.
A_______13_______12_______1
B_______10_______8________2
C_______8________6________2
D_______9________2________7
F_______10_______1________9
Tot______50______29________21
P(A|B) = P(A and B)/P(B)
P(A | ≤ 8) = = 1/21 = .05 rounded

SOLUTION: Grade___Students__>8 HRS.__<8 HRS. A_______13_______12_______1 B_______10_______8________2 C_______8________6________2 D_______9________2________7 F_______10_______1_____

SOLUTION: Grade_Students>8 HRS.<8 HRS. A_13_12_1 B_10_82 C_8__62 D_9__27 F_10_1_