[Tutor] Python OLS help

[Vadim Katsemba]

Hello there, I am having trouble running the Ordinary Least Squares (OLS)
regression on Spyder. I typed in lm =
smf.ols(formula='LATITUDE~DIAMETER',data=dataf).fit(), and I ended up
getting this error: ValueError: For numerical factors, num_columns must be
an int. How am I supposed to run the OLS, is there another module I need to
use? Any help would be appreciated.