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# statistics watch

1. A group of students believes that the time taken to travel to college, T minutes can be assumed to be normally distributed. Within the college 5% of students take at least 55 minutes to travel to college and 0.1% takes less than 10 minutes. Find the mean and standard deviation of T..
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(Original post by Fox Corner)
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3. (Original post by sunshinewothaya)
Within the college 5% of students take at least 55 minutes to travel to college
In other words, P(T >= 55) = 0.05. Which can be rephrased as P(T < 55) = 0.95.

0.1% takes less than 10 minutes.
and P(T < 10) = 0.001.

Recall that . You can find z with the probabilities above, your x's are 55 and 10, and the formula I gave will let you use this data to construct a pair of simultaneous equations which will yield the mean and standard deviation.

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