Hello Community,
My Question:
I have a question concerning how I can access the confidence intervals of the Actual by predicted graph below:
I attach the jmp file if you want to try yourselves. Now I am gonna tell you what I have tried up to know:
What I have tried:
I have save the columns “mean confidence limit formula as shown below:
However, when I try to reproduce the “Actual by Predicted plot”, the confidence intervals don’t look similar :
Actal by predicted plot:
Graph done in Graph builder with the saved columns (predicted, lower and upper confidence intervals):
So the saved columns clearly do not correspond to the confidence intervals in the “actual by predicted plot”
However, I realized that the saved confidence interval columns are actually the confidence intervals that appear in the profiler. Look at the two pictures below, one from the profiler and the other one built in the Graph builder:
This is interesting, but my original question is still unanswered:
How the confidence intervals from the “actual by predicted plot” are calculated ?
I also tried calculating them by myself in excel using the statistical equations for this, but still the confidence intervals I find are different from the “actual by predicted plot”:
Confidence interval calculated with t=0.05
Very different from
Conclusion:
Neither in JMP nor by my own calculation I have not been able to find the right way in which the confidence interval in the “actual by predicted” are actually calculated.
Could please someone help me to understand ?
Thank you,
Julian