Error in lm.fit(X, y) : 0 (non-NA) cases

This error message typically occurs when there are missing values (NA) in the data that is being used to fit a linear regression model using the lm() function in R. The error message indicates that there are no non-missing values in the data, which means that the model cannot be fit.

To resolve this error, you can check your data for missing values and either remove them or impute them before fitting the linear regression model. You can use functions such as na.omit() or complete.cases() to remove missing values, or use imputation methods such as mean imputation or multiple imputation to fill in missing values.