I am solving a question with
$$x_i = \{1.14, 2.23, 3.01, 4.55\}$$
$$y_i = \{10.77, 7.23, 5.31, 2.84\}$$ and to find out the best fit line of it.
mean of $x_i = 2.73$ mean of $y_i = 6.54$
and the $s_{xx}$ of it is $6.174$ after calculating but then i find out $s_{xy}$ is a negative number.
So is it normal and should i keep solving the question with $s_{xy}$ is a negative number?
Please help.