Question 1186253
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The scores on a national achievement exam are normally distributed with a mean of 500 
and a standard deviation of 100. If a student who took the exam is randomly selected, 
find the probability that the student scored below 600. Assume a normal distribution. 
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<pre>
Notice that 600 is one standard deviation from the mean 500.


According to the empirical rule, 68% of all scores are within one standard deviation 
from the mean.


Due to the symmetry of normal curve, it means that half of that, or 34% of all scores 
are in the interval [500,600].


Add to it 50% of scores that are under the mean, and you will get the <U>ANSWER</U>
to the problem's question of  50% + 34% = 84%.
</pre>

Solved.