Question 1207253
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English translation from Chinese


Find the specified area using a standard normal table.
Between one standard deviation below the mean and two standard deviations above the mean. 
(Round to four decimal places as necessary.
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Use the empirical rule.


Between one standard deviation below the mean and two standard deviations above the mean, the area is

    {{{0.68/2}}} + {{{0.95/2}}} = 0.34 + 0.475 = 0.815,  approximately.
</pre>

Solved.


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The Empirical Rule states that 68% of the data falls within one standard deviation, 
95% percent within two standard deviations, and 99.7% within three standard deviations from the mean.