1 It is estimated that 1 of the population is blood type AB

1) It is estimated that 1% of the population is blood type AB-.

During a blood drive Let X be the number of people who donate without B- blood donate before 4

people with A- blood donate.

a) What is the probability X=70?

2) Suppose P(A)=0.25, P(B)=0.4, P(A?B)=0.55.

a) Find P(A?B).

b) Find P(A|B).

c) Are A & B independent? (Justify your answer).

3) How many ways are there to pick 5 items from a group of 75 when order doesn

1) Question not clear

2) P(A int B) = 0.25+0.4-0.55 = 0.10

b) Find P(A|B) = P(AintB)/P(B) = 0.10/0.4 = 0.25

c) Are A & B independent?

P(AB) =0.10 and P(A) P(B) = 0.10

Hence they are independent

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3) I item in 75 ways

Ii item in 74 ways etc.

hence answer is 75P5 = 75!/70! = 2071126800

4)Mean 113

Median = 13

Mode =10

Ascending order

2,10,10,12,13,16,17,19,918

Least representative = Mode

b) P(X<70) = 8/9 = 0.889

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5) No of applicants he refuses to hire

Binomial distribution