Question

Hospital waiting room times are normally distributed with a mean of 38.12 minutes and a standard deviation of 8.63 minutes. What is the shortest wait time that would still be in the worst 20% of wait times?

Answer 1

Answer:

$x= 45.46$

Explanation:

given,

mean of hospital waiting (μ) = 38.12  min

standard deviation (σ) = 8.63 min

worst waiting time = 20%  

the are will be same as the = 100 - 20%

                                             = 80%

we have to determine the z- value according to 80% or 0.80

using z-table

     z-value = 0.85

now, using formula

       $Z = \dfrac{x-\mu}{\sigma}$

       $0.85 = \dfrac{x-38.12}{8.63}$

       $x-38.12 = 0.85\times {8.63}$

       $x= 45.46$