
192 Data Analysis and Statistics for Geography, Environmental Science, and Engineering
6.1.7 reGression throuGh the oriGin
Now, you may wonder about the meaning of the intercept. As shown earlier, we can use a t value
given by Equation 6.53 to determine that the intercept is signicant. In many cases, interpreting the
value of Y when X = 0 is meaningless since we cannot extrapolate outside the range for which we
derived the regression equation. However, there are cases where it makes sense to claim that the
intercept coefcient to be zero, that is to say, for the regression line to go through the origin. Some
of these cases are those for wh