[gnumeric] add some more explanations to VAR and VARA

[Andreas J. Guelzow <guelzow src gnome org>]

commit 2ce55fcc7f114be993fd37be76fe84d72f4fea59
Author: Andreas J. Guelzow <aguelzow pyrshep ca>
Date:   Thu Dec 10 18:55:03 2009 -0700

    add some more explanations to VAR and VARA
    
    2009-12-09  Andreas J. Guelzow <aguelzow pyrshep ca>
    
    	* functions.c (help_var): add some more explanation
    	(help_vara): ditto

 plugins/fn-stat/ChangeLog   |    5 +++++
 plugins/fn-stat/functions.c |    8 +++++++-
 2 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/plugins/fn-stat/ChangeLog b/plugins/fn-stat/ChangeLog
index 9f21ef4..2550b15 100644
--- a/plugins/fn-stat/ChangeLog
+++ b/plugins/fn-stat/ChangeLog
@@ -1,5 +1,10 @@
 2009-12-09  Andreas J. Guelzow <aguelzow pyrshep ca>
 
+	* functions.c (help_var): add some more explanation
+	(help_vara): ditto
+	
+2009-12-09  Andreas J. Guelzow <aguelzow pyrshep ca>
+
 	* functions.c (help_stdev): simplified
 	(help_vara): simplified
 	(help_stdeva): simplified
diff --git a/plugins/fn-stat/functions.c b/plugins/fn-stat/functions.c
index d729549..4e33175 100644
--- a/plugins/fn-stat/functions.c
+++ b/plugins/fn-stat/functions.c
@@ -80,10 +80,13 @@ static GnmFuncHelp const help_var[] = {
 	{ GNM_FUNC_HELP_ARG, F_("area1:first cell area")},
 	{ GNM_FUNC_HELP_ARG, F_("area2:second cell area")},
 	{ GNM_FUNC_HELP_DESCRIPTION, F_("VAR is also known as the N-1-variance.")},
+	{ GNM_FUNC_HELP_NOTE, F_("Since the N-1-variance includes Bessel's correction, whereas the N-variance calculated by VARPA or VARP does not, "
+				 "under reasonable conditions the N-1-variance is an unbiased estimator of the variance of the population "
+				 "from which the sample is drawn.")},
 	{ GNM_FUNC_HELP_EXCEL, F_("This function is Excel compatible.")},
 	{ GNM_FUNC_HELP_EXAMPLES, F_("Let us assume that the cells A1, A2, ..., A5 contain numbers 11.4, 17.3, 21.3, 25.9, and 40.1.")},
 	{ GNM_FUNC_HELP_EXAMPLES, F_("Then VAR(A1:A5) equals 117.64.")},
-	{ GNM_FUNC_HELP_SEEALSO, ("VARP,STDEV")},
+	{ GNM_FUNC_HELP_SEEALSO, ("VARP,STDEV,VARA")},
 	{ GNM_FUNC_HELP_EXTREF, F_("wiki:en:Variance") },
 	{ GNM_FUNC_HELP_EXTREF, F_("wolfram:Variance.html") },
 	{ GNM_FUNC_HELP_END }
@@ -2572,6 +2575,9 @@ static GnmFuncHelp const help_vara[] = {
 	{ GNM_FUNC_HELP_DESCRIPTION, F_("VARA is also known as the N-1-variance.")},
 	{ GNM_FUNC_HELP_DESCRIPTION, F_("To get the true variance of a complete population use VARPA.") },
 	HELP_DESCRIPTION_TEXT_INCLUSION,
+	{ GNM_FUNC_HELP_NOTE, F_("Since the N-1-variance includes Bessel's correction, whereas the N-variance calculated by VARPA or VARP does not, "
+				 "under reasonable conditions the N-1-variance is an unbiased estimator of the variance of the population "
+				 "from which the sample is drawn.")},
 	{ GNM_FUNC_HELP_EXCEL, F_("This function is Excel compatible.") },
 	{ GNM_FUNC_HELP_EXAMPLES, F_("Let us assume that the cells A1, A2, ..., A5 contain numbers and strings "
 				     "11.4, 17.3, \"missing\", 25.9, and 40.1.") },