double local fn CalcSD( x as double )
  static double n, sum, sum2
  n++
  sum += x
  sum2 += x * x
end fn = sqr( sum2 / n - sum * sum / n / n )

void local fn DoIt
  double testData(7) = {2,4,4,4,5,5,7,9}
  for int i = 0 to 7
    double x = testData(i)
    double a = fn CalcSD( x )
    printf @"value %.0f SD = %f", x, a
  next
end fn

fn DoIt

HandleEvents