R. B. Nottingham
= R. B. Nottingham
{c}
<R. B. Nottingham> coauthored <The Folded Normal Distribution by F. C. Leone and others> with <F. C. Leone> and <L. S. Nelson>, published in Technometrics in 1961. Their paper addressed measurements whose algebraic signs were not recorded. Even if a signed quantity follows a <normal distribution>, its recorded magnitude follows a different <probability distribution>.<The Folded Normal Distribution by F. C. Leone and others>[Primary byline, abstract and introduction: unsigned measurements and parameter estimation]{ref}
The practical issue is information loss during observation. If $X\sim N(\mu,\sigma^2)$ and the instrument reports $Y=|X|$, then $\mu$ and $-\mu$ produce the same <folded normal distribution>. Thus magnitudes alone cannot distinguish an offset to one side of a reference from an equally large offset to the other side. This conclusion follows from the observation rule, not from the quality of a numerical fitting method.
An illustrative inspection records distances from a reference line but omits which side each point lies on. A pair of signed readings $-2$ and $+2$ becomes two identical magnitudes $2$. Retaining the original signs would preserve a distinction that no later analysis of those two magnitudes can reconstruct. The paper's contribution is to treat this altered observation distribution explicitly rather than fit an ordinary signed <normal distribution> to magnitude data.
The cited work is jointly authored; the primary byline does not assign individual responsibility for particular formulas or tables. The printed initials are retained here without attaching unrelated biographical records to this author.