Question

A survey is taken on average commute time to work. The mean and standard deviation of the survey are as follows: Mean commute time: 30 minutes Standard deviation: 10 minutes 14. Use the mean and standard deviation above to calculate the z-score of a 45 minute commute to work. Explain what this z-score tells us.

Answer 1

This is a normal distribution question with


x = 45
P(x > 45.0)=?
The z-score at x = 45.0 is,


This implies that

This means, 6.68% people take more than 45 minutes of time to commute

PS: you have to refer z score table to find the final probabilities.
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