Question

Using a linear regression equation, how can I interpolate the value of X when I have a specific value for Y?

Answer 1

Make use of the inverse function of the least squares regression line

Explanation:

From the linear regression equation `Y=MX+C`, where `M` is the gradient or slope of the least squares line and `C` is the y-intercept of the least squares line, you may find the X-value by making use of the inverse function to obtain that
`X=(Y-C)/M`