Degrees of freedom

Degrees of freedom, according to my understanding should be n-1. But as I am observing in most of the questions (Schweser question bank), they have taken them as n-2. Any comment or clarification, would help me.

The number of degrees of freedom depends on how many parameters you’ve estimated.

In a multiple regression, for example, in which you have n data points and k independent variables and you’re estimating k slope coefficients and one intercept, dof = nk − 1.

What are types of problems in which you’re seeing dof = n − 2?

These are the kinds of things I can’t believe the prep providers and the CFAI fail to explain or even give the first sentence that s2000 provided. From the whacky misconception that multicollinearity inflates R2 or the F-statistic to the “mysteriously new” t-statistic for Pearson’s correlation coefficient… they look like a deer on ice.