if the mean is 70 minutes, then 90 minutes is 2 standard deviations above 70. if you look at the bell curve i drew, the percent of exams that took over 90 minutes is 2.5%
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Answer:
95%
Step-by-step explanation:
The empirical rule states that if data follows normal distribution then the percentage of observations falls within one, two and three standard deviation around the mean are
i) 68% falls within one standard deviation
ii) 95% falls within two standard deviation
iii) 99.7% falls within three standard deviation.
Hence 95% of the observations will fall within two standard deviations around the mean if the data follows normal distribution.
The sum of all angles in a regular octagon is 1080 degrees. Because all sides are the same (regular octagon), all of the eight angles are the same too, so we simply divide 1080 by 8 and that is the solution.
1080/8 = 135
