/// <summary>
/// This function return the value of probability density
/// function(PDF) for normal standard distribution with Z=z
/// and Z ~ N(0,1)
/// </summary>
/// <param name="z">double. z is standard value</param>
/// <returns>
/// The value of probability density function (PDF) for x
/// where Z ~ N(0, 1)
/// </returns>
public static double PDF(double z)
{
NormalFunction function = new NormalFunction();
return(function.Value(z));
}
/// <summary>
/// This function return the value of probability density
/// function(PDF) for normal distribution with X=x, mean mu,
/// and standard deviation sig.
/// </summary>
/// <param name="x">double. x is observing data</param>
/// <param name="mu">double. mu is mean of data</param>
/// <param name="sig">double. sig is standard deviation data</param>
/// <returns>
/// The value of probability density function (PDF) for x
/// where X ~ N(mu, sig)
/// </returns>
public static double PDF(double x, double mu, double sig)
{
NormalFunction function = new NormalFunction(mu, sig);
return(function.Value(x));
}