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A normal distribution has a mean of 50 and a standard deviation of 6. About 68 percent of its values lie between which two numbers?
A38 and 62
B44 and 56
C32 and 68
D47 and 53
Answer & Solution
Correct answer: B. 44 and 56
1. About 68 percent of values sit within one standard deviation of the mean.
2. One standard deviation here is 6, so step 6 either side of 50.
3. Below the mean gives 50 minus 6, which is 44.
4. Above the mean gives 50 plus 6, which is 56.
5. The pair 38 and 62 is two standard deviations out, which covers about 95 percent instead.
_Source: OpenStax High School Statistics (CC BY 4.0), section 6.1 The Standard Normal Distribution_
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