The probability of being a universal donor is 6% (O-negative-blood type). Suppose that 6 people come to a blood drive.' a) What are the mean and standard deviation of the number of universal donors among the 6 people? b) What is the probability that there are exactly three universal donors?

Step-by-step explanation:

Given

Let

A = Event of being a universal donor.

So:

Solving (a): Mean and Standard deviation.

The mean is:

The standard deviation is:

Solving (b): P(x = 3)

The event is a binomial event an dthe probability is calculated as:

So, we have:

94

step-by-step explanation:

average the numbers and use a variable to figure out the minimum to get a 90.

(79+94+91+92+x)/5=90

x = 94