The F–test   

The significance of the regression results can be tested by using the F- statistics. The F-statistics is a ratio which compares the explained sum of squares and the unexplained sum of squares.

Therefore, F = mean sum of squares due to regression
                       Mean sum of squares due to residual

For calculation purposes:
F = r² /K
    (1 – r²)/n-k-1

F statistics can then be used to test the hypothesis that the relationship between the dependent variables and all the independent variables is not significant.