topic Re: Regression Analysis in Discussions

Regression Analysis

none1 — Sat, 20 May 2017 10:29:52 GMT

Hello Everyne.

One new question: I have a regression line (please see attachment) Y xs X.

I have calculated the confidence intervals for Y as a function or X.

However based on this fit, when I want to get the confidence intervals of X how do I calculate them.

The reason for this question is that ofter times we obsere a response (Y) and then read back the X value from the regression line. Therefore when an X value is read out of this regression line, it should theoretically also have a confidence interval ?

I am much obliged for your kind assistance.

Re: Regression Analysis

txnelson — Sat, 20 May 2017 12:01:30 GMT

~~You can get the confidence interval for your X variable by running the Distribution Platform.~~

See Mark's response below

Re: Regression Analysis

Mark_Bailey — Sat, 20 May 2017 11:57:00 GMT

This is known as inverse prediction or the calibration problem. You have a standard curve and correctly fit Y (response) versus X (known levels). This result is available but not in the Bivariate platform that you used. Use the Fit Least Squares platform instead. Select Analyze > Fit Model. Enter your Y column in the Y role, enter your X column as an Effect, and click Run. Click the red triangle at the top and select Estimates > Inverse Prediction. Choose your confidence level and your desired type of interval. Enter up to eight Y values. Finally, use the option at the bottom to indicate if you want an interval estimate for the mean X (default) or the individual X value (check the box).

Re: Regression Analysis

none1 — Sat, 20 May 2017 11:58:59 GMT

Hi there,

You mean distribution X as Y (right) ?

But this is not very helpful, it generates no meaningful report. I would be obliged for your assistance .

Re: Regression Analysis

none1 — Sat, 20 May 2017 12:09:11 GMT

This result is available but not in the Bivariate platform that you used.

Use the Fit Least Squares platform instead.

Sorry, could not find this platform ?

Re: Regression Analysis

txnelson — Sat, 20 May 2017 12:24:56 GMT

The platform that Mark is referring to is:

Analyze==>Fit Model

Within it you can choose the Least Squares