Question

30)High blood pressure: A national survey reported that 30 % of adults in a certain country have hypertension (high blood pressure). A sample of 20 adults is studied. Round the answer to at least four decimal places. Part 1 of 4 (a) What is the probability that exactly 5 of them have hypertension? The probability that exactly 5 of them have hypertension is . Part 2 of 4 (b) What is the probability that more than 7 have hypertension? The probability that more than 7 have hypertension is . Part 3 of 4 (c) What is the probability that fewer than 4 have hypertension? The probability that fewer than 4 have hypertension is . Part 4 of 4 (d) Would it be unusual if more than 10 of them have hypertension? It ▼ (Choose one) be unusual if more than 10 of them have hypertension since the probability is .

Answer 1

It is a case of binomial distribution

with p = 0.30 and n = 20

(A) P(X=5) = binompdf(n,p,k)

setting n = 20,p = 0.30 and k = 5

we get

P(X=5) = binompdf(20,0.3,5)

= 0.1789

(B) P(X>7) = 1 - binomcdf(n,p,k)

setting n = 20, p = 0.30 and k = 7

we get

P(X>7) = 1- binomcdf(20,0.3,7)

= 1- 0.7723

= 0.2277

(C) P(X<4) = binomcdf(n,p,k-1)

setting n = 20 , p=0.30 and k = 4

P(X<4) = binomcdf(20,0.3,4-1)

= 0.1071

(D) P(X>10) = 1-binomcdf(n,p,k)

setting n = 20,p = 0.30 and k = 10

= 1- binomcdf(20,0.3,10)

= 1- 0.9829

= 0.0171

Yes, it would be considered as unusual because the calculated probability value (0.0171) is less than 0.05 value.