A certain characteristic in a large population has a distribution that is symmetric about the mean m. If 60 percent of the distribution lies within one standard deviation d of the mean, what percent of the distribution is less than m + d ?  Choose the most appropriate option:
A) 80%	B) 32%	C) 48%	D) 84%	E) 92%
This is easiest to solve with a bell-curve histogram. m here is equal to µ in the Gaussian normal distribution and thus m = 50% of the total population.   So, if 60% is one st.Dev, then on either side of m we have  60/2= 
<gadget id="calculator"> 60/2</gadget>
<output>30</output>
30%. So, 30% are to the right and left of m (= 50%). In other words, our value m + d = 50 + 30= 
<gadget id="calculator">50 + 30</gadget>
<output>80</output>
80% goingfrom the mean m, to the right of the distributionin the bell shaped histogram.. This means that 80% of the values are below m + d.   Like I said, doing it on a bell-curve histogram is much easier to fullygethow this works, or you could apply GM80%T percentile jargon/theory to it   80%
<result>A</result>
A certain characteristic in a large population has a distribution that is symmetric about the mean m. If 60 percent of the distribution lies within one standard deviation d of the mean, what percent of the distribution is less than m + d ?