Question

1. Please explain which rules of calculus lead from step 1 below to steps 2 and 3, and from step 3 to step 5:

Step 1: RSS = sum from i = 1 to n (yi - b0 - b1xi)^2

Step 2: deltaRSS/deltab0 = (- 2) sum from i = 1 to n (yi b0 - b1xi) = 0

Step 3: deltaRSS/deltab1 = (- 2) sum from i = 1 to n (xi(yi - b0 - b1xi)) = 0

Step 4: sum from i = 1 to n (yi) = b0n + b1 sum from i = 1 to n (xi) (normal equation 1)

Step 5: sum from i = 1 to n (xi yi) = b0 sum from i = 1 to n (xi) + b1 sum from i = 1 to n (xi^2) (normal equation 2)

Answer 1

Hope it helps.