Can someone please explain how the function is computed? I know you take the sum of Y starting from 1 minus Beta x 1. Looking at the bullet points on how the formula is computed I don't see where the 1/2N in front of the E is applied. What does the 1/2N mean ? -

Compute J (B) J ( B ) = : 2 N Li=1 (Yi - BX;)2 . B= 2 . Cost = cost for all three data points . Cost for i = 1: (Y; - BX;)2 = (1 - 2(1))2 = (-1)2 = 1 . Cost for i = 2: (Y; - BX;)2 = (2 - 2(2))2 = (-2)2 = 4 . Cost for i = 3: (Y; - BX;)2 = (3 - 2(3) )2 = (-3)2 =9 . Sum inside sigma = 1 + 4 + 9 = 14 Total cost = 14/6