In: Statistics and Probability
The personnel office at a large electronics firm regularly schedules job interviews and maintains records of the interviews. From the past records, they have found that the length of a first interview is normally distributed, with mean μ = 37 minutes and standard deviation σ = 7 minutes. (Round your answers to four decimal places.)
Seventeen first interviews are usually scheduled per day. What is the probability that the average length of time for the seventeen interviews will be 40 minutes or longer?
Solution :
Given that ,
mean = = 37
standard deviation = = 7
n = 17
= 37 and
= / n = 7 / 17 = 1.6977
P( 40) = 1 - P( 40)
= 1 - P(( - ) / (40 - 37 ) / 1.6977)
= 1 - P(z 1.767)
= 1 - 0.9614
= 0.0386
Probability = 0.0386