<https://boards.ngccoin.com/topic/425649-buy-the-coin-not-the-holder/#comment-9778808>
<http://schema.org/text>
"Each numerical grade can be represented by a normal distribution curve similar to this one. Most of the coins graded, for example MS-63, will fall within the two red arrow areas of the curve (one standard deviation). The yellow arrow areas (two standard deviations) will include coins that are labeled “MS-63” but are really either noticeably worse or better that most. The green arrow areas (three standard deviations) are coins labeled “MS-63” that actually fall outside of the “MS-63” grade, either worse (MS-62) or better (MS-64).\n \n\n\n\tTherefore each numerical grade overlaps those adjacent, independent of any official definition. This is the realm of the crack-and-resubmit person.\n \n\n\n\tFurther, the relationship between numerical grades and physical condition of coins is non-linear. This produces a somewhat different normal distribution curve for EACH numerical grade, and thus affects the proportion of coins in the overlapping areas.\n \n"
<https://boards.ngccoin.com/topic/425649-buy-the-coin-not-the-holder/>