Correlation and Regression Lines - A Quick Recap#1

Hackerrank Solution

Correlation and Regression Lines - A Quick Recap #1.py

@@ -1,17 +1,27 @@
+
 #RAMESH CHANDRA
 
 import math
 x = [15 , 12 , 8  , 8 ,  7 ,  7 ,  7 ,  6   , 5  , 3]
 y = [10  ,25 , 17  ,11 , 13 , 17 , 20 , 13 , 9  , 15]
+#calculate mean of x and y
 sum_x,sum_y=0,0
 for i in xrange(len(x)):
     sum_x,sum_y=sum_x+x[i],sum_y+y[i]
+
 mean_x = float(sum_x)/len(x)
 mean_y = float(sum_y)/len(y)
-A, B , C = 0,0,0;
+#now calculate r = A/sqrt(B*C)
+# A = sum ((x[i]-x_mean_x)*(y[i]-mean_y)) 
+# B = sum(x[i]-mean_x)^2
+# C = sum(y[i]-mean_y)^2
+
+A, B , C ,= 0,0,0;
 for i in xrange(len(x)):
     A += (x[i]-mean_x)*(y[i]-mean_y)
     B += (x[i]-mean_x)**2
     C += (y[i]-mean_y)**2
+#Co-relation Coefficient
 ans = float(A)/math.sqrt(B*C)
 print ans
+#for more info....go to this link   https://www.youtube.com/watch?v=2SCg8Kuh0tE