normalPDF — Defines a normal (Gaussian) probability density
function
numSigmas- Indicates how many standard deviations is represented by the uncertainty values given later. Integer value > 0.
In a normally distributed random variable, a symmetrical distribution of given standard deviation is assumed about the nominal value (which is given elsewhere in the parent element). The correlatesWith subelement references other functions or variables that have a linear correlation to the current parameter or function. The correlation subelement specifies the correlation coefficient and references the other function or variable whose random value helps determine the value of this parameter.