How do I get error average, median and std deviation between a predicted model and actual values

[#1]

I am using JMP 18 and did a fit least square to predict a varible using others. I would like to know were I can see the error % vs. actual

[#2]

First, welcome to the community.  It is very helpful to include data tables (or at least output screen shots) to help answer questions.

Now regarding your inquiry...Not sure what you are asking.  The RMSE is the standard deviation of the model and it is reported in the Summary of Fit window.  Also in that widow are the R-square and R-square adjusted.  These two statistics may be useful for determine how much of the variation in the data is explained by the model.

Usually one would use residuals analysis to determine how well the prediction model performs vs. actual values. There are a number of plots and statistics that can be created to perform, residuals analysis.  Is this what you want?