Re: OT: central limit theorem

On 4/26/2024 3:36 PM, John Larkin wrote:

On Fri, 26 Apr 2024 14:46:52 -0400, bitrex <user@example.net> wrote:
 

I have one of these inexpensive Ikea bookshelves for storing some of my
electronics books:
>
<https://www.ikea.com/us/en/p/laiva-bookcase-black-brown-40178591/>
>
I noticed the center shelf was starting to sag a few degrees. :( The
assembly manual specifies a weight limit of 33 lbs evenly distributed
which seemed like an oddly specific number. So I weighed the books on
the shelves, which aren't particularly well organized other than to
fully fill the available space widthwise on each shelf.
>
A random assortment of hardbacks and paperbacks, some are tall and
skinny, some are short and fat. And each shelf was clocking in at 33 lbs
+/- 2 lbs.
>
So I guess a heuristic for filling these shelves is just fill 'em up
then remove the heaviest book, and de-rate the center shelf by maybe 5-
10 lbs because it's unsupported by a backing.

 Composites, like the Ikea particle board, tend to sag. I got a nice
barbeque table where the propane tank can sit on the lower shelf, but
in a matter of days it took on a serous sag. It's some plastic
composite.
 Like many things that one buys these days, the first thing is to
redesign it.
 Add a center support of some kind.

They definitely have the "manufacturing" down to a science, though. I've assembled a number of their flat-packs over the years and I can't recall one that was ever short a part, or conversely, contained a single spare part.
Did Heathkit provide spares with their kits? Well, guess we know why they're out of business..