The mean of the standard normal graph shown is the middle point about which the graph is symmetric.
Hence, mean is 75.
Also, given that standard deviation is 6.
<u><em>What is 1 standard deviation from the "mean" mean?</em></u>
<em>75+6=81</em><em> and </em><em>75-6=69</em>
<em>So a value within 69 and 81 would be called within 1 standard deviation of the mean.</em>
So, calculating 2 standard deviation from the mean as:
75+6+6=87 and 75-6-6=63
So a value within 63 and 87 would be called within 2 standard deviation of the mean.
84 falls in this category, so we can say answer choice B is correct.
ANSWER: B
