What does obs confidence interval in statsmodels linear regression in Python

Question

Once you run the regression model with the module 'statsmodels' in Python, you can get the prediction with these confidence intervals: mean_ci_lower mean_ci_upper obs_ci_lower obs_ci_upper

I know what mean_ci means but I have no idea what obs stands for.

Answer 1

obs_ci is the prediction interval, i.e. a confidence interval for a new observation.

It combines the uncertainty about the mean estimate with the randomness of a new observation for given mean. It assumes that residuals are distributed close to normal distribution, uses either normal or t distribution for the prediction interval and is therefore only approximate.