Answer: Choice C
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Step-by-step explanation:
The mean is 98, so that's the center of the distribution. This is where the highest point occurs because the most people are clustered around here. This rules out choice A and the answer is between B or C.
One standard deviation above the mean is 98+6 = 104. All we do is add on the standard deviation (6) to the mean (98) to get 104.
One standard deviation below the mean is 98-6 = 92
The graph that has tickmarks at 92 and 104 indicate we are exactly 1 standard deviation from the mean (98)
Similarly, 2 standard deviations above the mean is at 98+2*6 = 98+12 = 110. Or you could say 104+6 = 110.
2 standard deviations below the mean would get us to 98-2*6 = 98-12 = 86
The same idea applies to 3 standard deviations as well.
All of this matches with graph C. We can eliminate graph B by noticing that something like 95 is not a result of 98-6.