Question

The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.6 days and a standard deviation of 1.8 days.

What is the probability of spending more than 4 days in recovery? (Round your answer to four decimal places.)

I have been stuck on this question for an hour.

Answer 1

Define random variable X: Patient recovery time.

X is normally distributed with mean = 5.6 and standard deviation = 1.8

Here we have to find P(X > 4)

                                         where z is standard normal variable

                       = P(z > -0.89)                    (Round to 2 decimal)

                      = 1 - P(z < -0.89)

                      = 1 - 0.1867              (From statistical table of z values)

                      = 0.8133

The probability of spending more than 4 days in recovery is 0.8133