# Ivar error with Fit inside Plot [duplicate]

I'm trying to plot this Plot[Fit[med,{1,x},x],{x,0,10}] Why this doesn't work? I find out that if I do Plot[Evaluate@Fit[med,{1,x},x],{x,0,10}] works fine. But can somebody explain me why this happens in first place?

Plot has attribute HoldAll, therefore the expression Fit is hold in an unevaluated form.

Using

Attributes@Plot

(* out *)
{HoldAll, Protected}


reveals the attributes

• Thanks, and why this is useful? I mean, the holdall – Kafkarudo Aug 23 '14 at 13:46
• Sometimes we don't want the argument to be evaluated at once, please have a look at the examples given by documentation center – hieron Aug 23 '14 at 13:50