# 2311: Confidence Interval

 Confidence Interval Title text: The worst part is that's the millisigma interval.

## Explanation

 This explanation may be incomplete or incorrect: Created by a TERRIBLE MODEL. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.If you can address this issue, please edit the page! Thanks.

Graphs of continuous functions' predicted values often show confidence intervals, a region (either shaded or marked with dotted lines, the latter used here) that indicates the margin of error for the prediction at any point.

## Transcript

(A curved graph. Two gray lines outside of the chart.)
[Caption below the panel:]
Science tip: If your model is bad enough, the confidence intervals will fall outside the printable area.

# Discussion

What's a millisigma? 162.158.107.209 03:31, 26 May 2020 (UTC)Ven

Not an official scientific term - most likely referring to standard deviation. One standard deviation, or sigma, is the 68.3 % of values lying around the mean in a normal distribution. A millisigma in a standard deviation would be .0683 % of a normal distribution so that much variation would be bad? Not sure. 172.69.63.203 05:23, 26 May 2020 (UTC)
Actually, if you integrate a normal distribution $\mathcal{N}(0,1)$ from $-\frac{\sigma}{1000}=-0.001$ to $+\frac{\sigma}{1000}=0.001$, you'll get a range of about 0.08% of all values. This would be bad because it would mean that, as big as the confidence interval appears in the picture, the more meaningful 1- or 3-sigma interval (whose size represents the uncertainty of the model) would be larger by a factor of 1250 or 3750, respectively. --Koveras (talk) 08:38, 26 May 2020 (UTC)
Perhaps you heard about Six Sigma, a quality method used by General Electric (among others) to keep specifications and processes within tiny tolerances. The six sigmas mean that even absolute (so-called) outliers in your production are within the strict tolerances. With milli-sigmas it is extremely seldom to get an acceptable result at all. Sebastian --108.162.229.234 10:53, 26 May 2020 (UTC)

Can it be related to Covid19 pandemic and all those graphs that try to predict if it is in decline or not? Tkopec (talk) 08:27, 26 May 2020 (UTC)

I didn't think so, until I read the discussion of Millisigma above, and realized that the millisigma is awfully close to your chance, worldwide, of dying from COVID-19. A millisigma of the population will die.Seebert (talk) 14:56, 27 May 2020 (UTC)
No. But maybe it's related to the recent Mt. St. Helens comic... :p Seriously, not everything has to be related to the hot-button topic of the day.
Au contraire, mes amis, it is obvious to me that 1: Barrel - Part 1 is about socially isolating away from the virus. (Remember to sign?) 162.158.158.237 10:56, 26 May 2020 (UTC)

Isn't the (or a) reason that this is a science tip is that having confidence lines are off the page makes it look as if the prediction is precise? 141.101.99.65 11:35, 26 May 2020 (UTC)

Real life example of this comic (scroll down to Alaska, Hawaii, Montana, etc): https://rt.live/ Godzilla (talk) 15:26, 26 May 2020 (UTC)

The smaller the error or uncertainty value, the larger the confidence number. A confidence value of less than 1 is usually considered unreliable, but may justify further experiments/observations. Confidence that is practically indistinguishable from 0 means the result is only marginally better than pure chance or a result showing no correlation. Said another way, you have no confidence in your observations. Nutster (talk) 13:41, 26 May 2020 (UTC)

Doesn't it bother anybody else that the inside of the P, R and D characters are filled with gray in the comic? Divieira (talk) 17:43, 22 June 2020 (UTC)

## Suggestions for improvement on the shape of the two confidence intervals

The confidence interval of interpolation (usually just the "confidence interval of prediction," not the confidence of the mean, but that's another story) should not be confused with the confidence interval of extrapolation, which should be called the "confidence interval of prediction" if the confidence interval of the curve fit wasn't called that.

I think mathematicians and cartoonists need to team up to fix this. 172.68.142.47 17:57, 26 May 2020 (UTC)