Content-Type: text/shitpost


Subject: Mysterious markings on my Water-Pik
Path: you​!your-host​!walldrug​!prime-radiant​!skordokott​!mechanical-turk​!berserker​!plovergw​!shitpost​!mjd
Date: 2018-05-21T18:47:39
Newsgroup: talk.mjd.water-pik
Message-ID: <c8e66ec10387054a@shitpost.plover.com>
Content-Type: text/shitpost

Here are the volume graduations on the tank of my Water-Pik:

The graduations are in two
columns.  The left column is marked ‘OZ.' and contains the numbers 19,
16, 12, 9, 6; the right column is marked ‘ML.’ and contains the
numbers 600, 500, 400, 300, 200, 100.

Now what is going on here?

I measured the heights of the marks in pixels in the photo:

A smaller part of the same
picture, this time with perfectly horizontal yellow and orange lines
drawn across it at the same heights as the graduations.

OZ.ML.pixels
 600 1094
19  963
 500 838
16  707
 400 590
12  456
 300 335
9  199
 200 86
6  -50

Then I ran linear regressions.

For the milliliters values, the line is $$\text{px} = 2.59\text{ ml } -419$$ with a correlation of 99.9988%. Fair enough.

For the ounces values, the line is $$\text{px} = 76.5\text{ oz } -495$$ with a 99.86% correlation. That slope of !!76.5\frac{\text{px}}{\text{oz}}!! is exactly the same as the !!2.59\frac{\text{px}}{\text{ml}}!! slope in the previous line. If we correct the two suspicious ounce numbers from 16 and 19 to 15 and 18, the correlation goes up to 99.9988% but the slope increases to !!84.5\frac{\text{px}}{\text{oz}}!!.

I guess the next step would be to measure the amounts but


Addendum: That's the point at which I lost interest and broke off mid-sentence. It's now about 24 hours later and I've decided to publish what I have.

Enjoy!