1) There is a 10% chance that a randomly selected individual will have O-negative blood.Suppose we randomly select 20 individuals from the population and test them for O-negative blood. LetXdenote the number of individuals in the sample that have O-negative blood.

(a)What is the distribution ofXin conventional statistical notation?(2 marks)

B(20, 1.8)

B(20, 0.90)

B(0.10, 20)

B(20, 0.10)

N(20, 0.01)

(b)What is the probability that at least 4 individuals in the sample have O-negative blood?(2 marks)

0.133

0.0432

0.9568

0.8670

0.3458

(c)What is the probability that less than 7 individuals in the sample have O-negative blood?(2 marks)

0.4532

0.3917

0.0004

0.9976

0.9996

(d)What is the P(1 < X< 6) equal to?(2 marks)

0.6059

0.8760

0.7341

0.3987

0.5970

(e)How many adults in the sample do we expect to have O-negative blood?(2 marks)

1.8

2

18

15

13

(f)What is the variance ofX?(2 marks)

1.34

18

1.8

2

15