Question

The U.S. national average door-to-doctor wait time for patients to see a doctor is now 21.3 minutes. Suppose such wait times are normally distributed with a standard deviation of 6.7 minutes. Some patients will have to wait much longer than the mean to see the doctor. In fact, based on this information, 3% of patients still have to wait more than how many minutes to see a doctor?

(Round z value to 2 decimal places. Round your answer to 2 decimal places.)

Answer 1

solution

Given that,

mean = = 21.3

standard deviation = =6.7

Using standard normal table,

P(Z > z) = 3%

= 1 - P(Z < z) = 0.03

= P(Z < z ) = 1 - 0.03

= P(Z < z ) = 0.97

= P(Z < z ) = 0.97

z = 1.88 (using standard normal (Z) table )

Using z-score formula  

x = z * +

x= 1.88*6.7+21.3

x= 33.896

x= 33.90