Answer: the probability that between 15% and 20% of the donors on a given day have a blood type of B is 0.3944
Step-by-step explanation:
Given that;
Binomial Distribution
n = 80
p = 0.15
q = 1 - p = 0.85
Mean = μ = np = 80 X 0.15 = 12
SD = σ = √(npq) = √(80 x 0.15 x 0.85) = -3.1937
Now; Assumptions in normal distribution to binomial distribution
- The sample size = n = 80 > 30 . Large sample
- np = 80 × 0.15 = 12 > 10
- nq = 80 × 0.85 = 68 > 10
so
80 × 0.15 = 12
80 × 0.20 = 16
To find P(12 < X < 16):
Z = (16 - 12) / 3.1937
= 4 / 3.1937
= 1.2525
Table of Area Under Standard Normal Curve gives area = 0.3944
Therefore the probability that between 15% and 20% of the donors on a given day have a blood type of B is 0.3944
