Error in cor(data_factor) : 'x' must be numeric

This error message is indicating that the function cor() is being applied to a non-numeric dataset, which is not allowed. The cor() function is used to calculate the correlation between two numeric variables.

To resolve this error, the dataset needs to be converted to a numeric format before applying the cor() function. This can be done by using the as.numeric() function to convert the data to a numeric format.

Alternatively, if there are non-numeric variables in the dataset that are not needed for the correlation calculation, they can be removed using subsetting or by selecting only the numeric variables in the dataset.