Question #fa68c

1 Answer
Will
Apr 25, 2017

#97.72 %#

Explanation:

we can normalize this and see that at mean of 70 that 90 minutes is 2 standard deviations away.

we know that the empirical rule states that the probability for 2 sd from the mean of a normal distribution is #95%# but this is for two tails. One approach is to look up the answer in a z table with one tail which shows #97.72 %#

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