According to a hospital administrator,historical records over the past 10 years have shown that 20 percent of the major surgery patients are dissatisfied with after-surgery care in the hospital.A scientific poll based on 400 hospital patients has just been conducted.What is the probability that at least 70 patients will not be satisfied with the after-surgery care?
A)89.44%
B)39.44%
C)10.56%
D)78.88%
E)84.49%

Question

Quizplus · Accepted Answer

The probability of dissatisfaction is 0.20. Using a binomial distribution with n=400 and p=0.20, we calculate the probability of at least 70 dissatisfied patients (X ≥ 70). This is equivalent to 1 - P(X ≤ 69). Using normal approximation, the probability is approximately 89.44%.

According to a Hospital Administrator,historical Records Over the Past 10