I did a quick search and didn't come across a post that covered this bug in line(X,Y). If the vector Y holds all-zeros then the line function (linear regression) fails. Oddly, the error message varies.
In some cases the message is:
"The calculation resulted in a vector with no elements."
In more cases, the message reads:
"Object reference not set to an instance of an object."
That's an obscure bug! It works fine if Y is a vector with all the elements identical, unless all the elements are 0. The slope, intercept, and medfit functions all work even if Y is all zeros.
