Question

1. In Blood Donation Camp, we took a sample of 148 donors, 41 had type A+ blood, 19 had type O+ blood, 28 had type B- blood, 46 had type A-, 10 had type AB+ and 4 had type AB- blood. Set up a frequency distribution and find the following probabilities.

a. A person has type A- blood.
b. A person has type AB+ or type AB- blood.
c. A person has neither type B+ nor type A+ blood.

Answer 1

Frequency distribution:

Type Number

A+   41

O+   19

B-   28

A-   46

AB+   10

AB-   4

total   148

Probabilities:

a. A person has type A- blood: $p = Number(A-) / total = 46 / 148 = 0.31$

b. A person has type AB+ or type AB- blood: $p = (Number(AB+) + Number(AB-)) / total = (10 + 40) / 148 = 0.09$

c. A person has neither type B+ nor type A+ blood: $p = (total - Number(B+) - Number(A+)) / 148 = (148 - 0 - 41) / 148 = 0.72$