Question

The distribution of blood types in the United States is as follows, where positive and negative refer to the Rhesus (Rh) factor:

O-positive:       37 %

O-negative:      7 %

A-positive:       35 %

A-negative:      6 %

B-positive:       9 %

B-negative:      2 %

AB-positive:     3 %

AB-negative:    1 %

If you randomly select 20 people from the population and measure Rh factor, what is the probability of each of the possible outcomes?   Create a histogram, and determine the probability that

a)  none are Rh negative

b)  three are Rh negative

c)  more than three are Rh negative

Answer 1

here from abve distribution;

P(Rh negative)

=P(O-negative)+P(A-negative)+P(B-negative)+P(AB-negative)=0.07+0.06+0.02+0.01=0.16

hence from binomial distribution P(X=x)=

belw is the histogram:

a)P( none are Rh negative)= =0.0306

b)P( three are Rh negative)= =0.2410

c)

P( more than three are Rh negative) =P(X>3) =1-(P(X=0)+P(X=1)+P(X=2)+P(X=3))

=1- =1-0.5990 =0.4010