SOLUTION: The time it takes Jessica to bicycle to school is normally distributed with a mean time of 15 minutes and variance of 4 minutes. Jessica has to be at school at 8 am what time shoul

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Question 1168393: The time it takes Jessica to bicycle to school is normally distributed with a mean time of 15 minutes and variance of 4 minutes. Jessica has to be at school at 8 am what time should she leaves her house so she will be late only 4% of the time ?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The 4% is the upper 96 percentile of the distribution, where z=1.75
z=(x-mean)/sd
1.75=(x=15)/2. since variance is 4 minutes^2 (the ^2 is needed for units), the sd is 2 minutes.
3.5=x-15
x=18.5 minutes
Leave for school at 7:41.30 am