Hopefully I'm asking this in the correct section. So I've got a graph with a linear trend of data and a best fit line plotted. The data points on the main graph obviously each have their own error bars. I've also made a subplot of residuals.
My question is: do the residual subplot's data points normally have to have error bars and if so, are these error bars the same ones as those on the main graph? I ask because I thought that perhaps the error on the gradient and the error on the intercept (calculated by Excel's LINEST in my case) contribute to the error on the residual data point which would mean I can't use the same error bars as those used on the main graph? Or am I wrong here?
Note: in my case, only the dependent variable has error - the independent variable, i.e. x axis does not have error.
Many thanks for any help.