Make documentation Sec 26.1 more consistent and Sec 25.4 clearer (bug #52685) * corr.m: Add space in LaTeX formula. For the example, place variables in a @var qualifier. * cov.m: Use @var in LaTeX for x and y when referring to function input vector. Correct Octave-help formula by placing parentheses around N-1 so that -1 is in the denominator. Define N after the formula in which it is used. * gls.m: Define what GLS stands for. Use @var instead of @math for function input and output variables. Move the description of matrix O and scalar s to a third paragraph, ensuring s is lower case. Give a little more context to the description of X and Y in the second paragraph. Add an expansive paragraph three for details about the error variables E including the description of O and s along with their dimensions. Add "matrix" before B and "scalar" before s for clarity. Place @var around variables r, y, x and beta to make those upper case in Octave-help. * histc.m: Use LaTeX math rather than @code for the @tex scenario. * kendall.m: Treat tau differently for LaTeX and Octave-help scenarios. Add space in LaTeX formulas. Treat tau as @var in Octave-help case. Use lower case 'i' for index variable and upper case 'N' for vector length. * kurtosis.m: For mean value of x, use script rather than non-script. Define N after the formula in which it is used for Octave-help case. * mean.m: Indicate N is number of elements. Use @var on input vector x for Octave-help case. * meansq.m: Indicate N is number of elements, but drop the reference to mean value because there is none. Use @var on input vector x for Octave-help case. Use "If x is a matrix" consistent with all others. * median.m: Indicate N is number of elements for LaTeX case. For Octave-help place some vertical lines to represent case curly-bracket. Place @math around N. Define an intermediate vector S representing sorted X and use that in the math formula. * moment.m: Define x-bar as mean and N as number of elements. Use @var on x and p in the Octave-help formulas. * ols.m: Define meaning of OLS. Add @var to LaTeX variables to make them non-script vectors. Use @var instead of @math for function input and output variables. Use hyphens for matrix dimensions in Octave-help formula. Move the description of matrix S to a third paragraph. Give a little more context to the description of X and Y in the second paragraph. Add an expansive paragraph three for details about the error variables E including the description of matrix S along with its dimensions, ensuring S is upper case. Add "matrix" before B for clarity. Make the definition of SIGMA one line for appearance in Octave-help. * prctile.m: Change a mistaken 'y' to 'q' to work in LaTeX as well. * quantile.m: Use @var{method} rather than METHOD. Break up all the method formulas for p(k) into LaTeX and Octave-help versions for better control. Use upper case N for the length of P. * skewness.m: Remove @var from x when referring to vector elements in LaTeX. Indicate N is number of elements. * spearman.m: Break into separate LaTeX and Octave-help cases rather than use @code for LaTeX. Use Greek symbol rho in LaTeX. * std.m: Add @var to x variable to indicate LaTeX or Octave-help vector. Add clarification about N being number elements of x to both LaTeX and Octave-help formulas. * var.m: Indicate N is number of elements. Apply @var to x to show it is a vector. Change == to "is equal to" for normal text.

--- a/scripts/statistics/base/skewness.m	Wed Jan 03 21:49:38 2018 -0800
+++ b/scripts/statistics/base/skewness.m	Wed Dec 27 23:38:25 2017 -0600
@@ -27,9 +27,9 @@
 ## @tex
 ## $$
 ## {\rm skewness} (@var{x}) = {{{1\over N}\,
-##          \sum_{i=1}^N (@var{x}_i - \bar{@var{x}})^3} \over \sigma^3},
+##          \sum_{i=1}^N (x_i - \bar{x})^3} \over \sigma^3},
 ## $$
-## where $N$ is the length of @var{x}, $\bar{@var{x}}$ its mean and $\sigma$
+## where $N$ is the length of @var{x}, $\bar{x}$ its mean and $\sigma$
 ## its (uncorrected) standard deviation.
 ## @end tex
 ## @ifnottex
@@ -52,7 +52,7 @@
 ## @tex
 ## $$
 ## {\rm skewness} (@var{x}) = {\sqrt{N (N - 1)} \over N - 2} \times \,
-##   {{{1 \over N} \sum_{i=1}^N (@var{x}_i - \bar{@var{x}})^3} \over \sigma^3}
+##   {{{1 \over N} \sum_{i=1}^N (x_i - \bar{x})^3} \over \sigma^3}
 ## $$
 ## @end tex
 ## @ifnottex
@@ -65,6 +65,8 @@
 ## @end group
 ## @end example
 ##
+## where @math{N} is the length of the @var{x} vector.
+##
 ## @end ifnottex
 ## The adjusted skewness coefficient is obtained by replacing the sample second
 ## and third central moments by their bias-corrected versions.