I have a dataset as following:
This is test case 1. My goal is to fill the missing years data. As the age sex and smoking is not changing so I have to predict the condition and percent data for year 0 to all the way 54. I found high correlation between condition and percent variable. This seems easy. But I am a bit confused now. Should I have to use multivariable regression? what would be the most best method to approach?