? see the question carefully, its not at all assignment request , its just for

i need this one fully explained as you can well understand after seeing the file that i only need to understand the concepts . i am attaching excel workbook as well I have used k = 2. But randomly. Author used k = 3. I don’t understand why. Why +/- ks? How does this regression with these limits make a good prediction? Thanks. you can code example so that i can understand better how much ? see the question carefully, its not at all assignment request , its just for my understanding 3 to 4 pages will be good