Question

Heart failure is due to either natural occurrences (86%) or outside factors (14%). Outside factors are related to induced substances or foreign objects. Natural occurrences are caused by arterial blockage, disease, and infection. Suppose that 18 patients will visit an emergency room with heart failure. Assume that causes of heart failure between individuals are independent.
Round your answers to three decimal places (e.g. 98.765).

(a) What is the probability that 3 individuals have conditions caused by outside factors?

Probability =

(b) What is the probability that 3 or more individuals have conditions caused by outside factors?

Probability =

(c) What is the mean and standard deviation of the number of individuals with conditions caused by outside factors?

Mean =

Standard deviation =

Answer 1

Given are the following data: 

Heart failure causes:

84% natural occurence
16% outside factors
18 individuals (sample size) 

1. What is the probability that 3 individuals have conditions caused by outside factors?

Probability = 3/18 * 0.16 = 0.0267 or 2.67%