SOLUTION: A lawyer commutes daily from his suburban home to his midtown office. On the average the trip one way takes 24 minutes, with a standard deviation of 3.8 minutes. Assume the distrib

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Question 843074: A lawyer commutes daily from his suburban home to his midtown office. On the average the trip one way takes 24 minutes, with a standard deviation of 3.8 minutes. Assume the distribution of trip time to be normally distributed.
a. What is the probability that a trip will take at least ½ hour?
b. Find the probability that 2 of the next 3 trips will take at least ½ hour.
c. What is the probability that a trip will take 20 to 23 minutes?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

mean 24min, sd = 3.8

Using TI Calculator

a. What is the probability that a trip will take at least ½ hour(30mim)?  

normalcdf(smaller, larger, µ, σ)= normalcdf(30, 9999, 24, 3.8).

Note: The 9999 is used as the larger value to be at least 5 standard deviations from the mean.

 b. Find the probability that 2 of the next 3 trips will take at least ½ hour.

 binompdf(n, p, x-value)=  binompdf(3, p, 2).

 c. What is the probability that a trip will take 20 to 23 minutes?

normalcdf(smaller, larger, µ, σ)= normalcdf(20, 23, 24,3.8).