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Applications of Normal Distribution

berrysryummy

New member
Joined
Nov 1, 2015
Messages
1
Here is the problem:

Megan drives to work each morning. Her commute time is normally distributed with mean 30 minutes and standard deviation 4 minutes. Her workday begins at 9:00AM. At what time should she leave for work so that the probability she is on time is 95%?

I know the value of x bar, sigma, and z of alpha over 2, but I have no idea where to get n. Am I using the completely wrong formula?

x bar = 30
sigma=4
z of alpha over 2= 1.95996


I'm using x bar +/- z* alpha times sigma over the square root of n.
 

maddy23

New member
Joined
Nov 4, 2015
Messages
2
did you ever figure out how to do this?

did you ever figure out how to do this? this is my math problem this week and i'm stuck. thanks
 

maddy23

New member
Joined
Nov 4, 2015
Messages
2
did you ever figure out how to do this?

did you ever figure out how to do this? This is my math problem this week and i'm stuck. thanks
 
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