I am fitting a linear regression line to my data and computing the confidence interval for some predicted $y$ (independent variable) (<http://people.stfx.ca/bliengme/ExcelTips/RegressionAnalysisConfidence2.htm>).


Now I want to do the inverse. I need a way to measure the confidence for some predicted $x$ (dependent variable) using the same regression. How can I achieve this?


Thank you!



Linear Regression Confidence Interval
Usually you predict a dependent variable y and calculate a confidence interval, i.e. given x0, you calculate [y-, y+] where y will probably lie in.


For the reverse, if you have a y0 and want to find [x-, x+] for whatever reasons, regression will not help.


The appropriate tool for this kind of analysis could be structural equations modeling [1]


[1] <http://en.wikipedia.org/wiki/Structural_equation_modeling>


