Added comments

Author: josh0306

src/DataFrame/DataFrame.class.st

@@ -906,6 +906,7 @@ DataFrame >> first [
 
 { #category : #statistics }
 DataFrame >> firstQuartile [
+    "25% of the values in a set are smaller than or equal to the first Quartile of that set"
 
 	^ self applyToAllColumns: #firstQuartile
 ]
@@ -1201,6 +1202,7 @@ DataFrame >> inspectionItems: aBuilder [
 
 { #category : #statistics }
 DataFrame >> interquartileRange [
+	"The Inter Quartile Range is the difference between the third Quartile and the first Quartile"
 
 	^ self applyToAllColumns: #interquartileRange
 ]
@@ -1276,6 +1278,7 @@ DataFrame >> max [
 
 { #category : #statistics }
 DataFrame >> median [
+   "50% of data points have a value smaller or equal to the median . The median of a set of values is the middle value of the set when the set is arranged in increasing order."
 
 	^ self applyToAllColumns: #median
 ]
@@ -1444,6 +1447,7 @@ DataFrame >> privateRowNames: anArray [
 
 { #category : #statistics }
 DataFrame >> range [
+	"Range is the difference between the highest value and the lowest value in a set"
 
 	^ self applyToAllColumns: #range
 ]
@@ -1974,6 +1978,7 @@ DataFrame >> sortDescendingBy: columnName [
 
 { #category : #statistics }
 DataFrame >> stdev [
+   "Standard deviation is a measure of how dispersed the data is in relation to the average"
 
 	^ self applyToAllColumns: #stdev
 ]
@@ -1995,6 +2000,7 @@ DataFrame >> tail: aNumber [
 
 { #category : #statistics }
 DataFrame >> thirdQuartile [
+   "75% of the values in a set are smaller than or equal to the third Quartile of that set"
 
 	^ self applyToAllColumns: #thirdQuartile
 ]
@@ -2041,6 +2047,7 @@ DataFrame >> transposed [
 
 { #category : #statistics }
 DataFrame >> variance [
+   "variance measures how far each number in the set is from the average value of the set. It is the square of standard deviation."
 
 	^ self applyToAllColumns: #variance
 ]