Re: Leave it to beaver season 3?
Radioman ..... That scene with Fred yelling up the stairs at Clarence/"The Lump" is a funny one indeed. But your chronology is not quite correct. Fred had already completed his phone call to Ward by the time he started screaming for Lumpy to come downstairs. (Lumpy is never seen "lumbering" down the stairs either.)
The episode is Season 2's "The Lost Watch", and that ep. features another good "Yelling Up The Stairs" scene too...the one at the start of the program which has Ward screaming at the top of his lungs for Wally. (That scene, btw, is rarely seen, if ever, in the hacked-up, shortened syndicated prints of that ep., which makes it all the more special on the DVD.)

BTW, just check out those "baseball" scenes in the "Lost Watch" episode and take note of the incredibly-clear PQ on the DVD. Pristine in every way, without a hint of grain (just like all other "out-of-doors" scenes on the Beaver DVDs, which sparkle like brand-new).
It makes me yearn all the more for the final seasons of the series, which feature even more "outdoor" camerawork.