#### Rory

##### Closed Account

A 2021 study of 485 serial killers proposed that certain astrological signs were overrepresented (and others therefore underrepresented) with "key findings" being:

A different 'study' of 487, however, found different results, with Capricorn (55) and Leo (46) topping the charts, and Taurus (22) and Cancer (34) being the most sedate.

Now, while these results - different though they are - might appear "statistically significant" (and therefore lend some much-needed credence to astrology) there's quite a simple explanation: what we're seeing here is an example of

To demonstrate this I made a simple spreadsheet that simulates 485 occurences of a thing that can be split into 12 equally sized 'pots'.

Here in column A I list the numbers 1 to 485 and in column B I use

Each number stands for a sign in the zodiac and the test is repeated 10 times to give more accuracy (one hundred or one thousand times would be better though):

As we can see, random chance suggests that a normal result using 485 occurences/12 'pots' predicts an expected range of around 18 to 58 - which encompasses the whole range of figures discovered by the studies (in repeating the test I received highs of 64; while 18 was the low).

The results therefore are entirely what is expected due to chance.

The fallacy seems to be built on two things: 1) the idea that 500 is a reasonable sample size (I would say several tens of thousands would be more like it, and even then there would be noticeable variations); and 2) a misunderstanding of how probability works, even among academics and those who understand p-factors, which leads them to expect the "result by chance" to equal

Good news for Capricorns and Cancers.

External Quote:* Four signs — Cancer, Pisces, Sagittarius, and Scorpio (46 each) — account for almost 40 percent of serial killers. Gemini and Taurus combined account for only 11 percent.

* Killers born in the sign of Capricorn accounted for more victims total and on average than those in any other sign. Combined, they killed more than 800 people, or 19 on average; the lowest average was for Virgo killers, with seven victims each.

* The water signs (Cancer, Pisces, and Scorpio) accounted for the highest number of killers and victims in our analysis — 28 percent of killers and 27 percent of victims.

https://www.astrology-zodiac-signs.com/blog/most-common-zodiac-signs-of-serial-killers/

A different 'study' of 487, however, found different results, with Capricorn (55) and Leo (46) topping the charts, and Taurus (22) and Cancer (34) being the most sedate.

Now, while these results - different though they are - might appear "statistically significant" (and therefore lend some much-needed credence to astrology) there's quite a simple explanation: what we're seeing here is an example of

**Yonezawa's Fallacy**. In a nutshell, despite a sample size of almost 500, it's still nowhere near enough to provide anything approaching a usable result.To demonstrate this I made a simple spreadsheet that simulates 485 occurences of a thing that can be split into 12 equally sized 'pots'.

Here in column A I list the numbers 1 to 485 and in column B I use

*=randbetween(1,12)*to generate a random number between 1 and 12:Each number stands for a sign in the zodiac and the test is repeated 10 times to give more accuracy (one hundred or one thousand times would be better though):

As we can see, random chance suggests that a normal result using 485 occurences/12 'pots' predicts an expected range of around 18 to 58 - which encompasses the whole range of figures discovered by the studies (in repeating the test I received highs of 64; while 18 was the low).

The results therefore are entirely what is expected due to chance.

The fallacy seems to be built on two things: 1) the idea that 500 is a reasonable sample size (I would say several tens of thousands would be more like it, and even then there would be noticeable variations); and 2) a misunderstanding of how probability works, even among academics and those who understand p-factors, which leads them to expect the "result by chance" to equal

*occurences divided by 'pots'*- eg, 40 to 41 - whereas the actual chance result is a range that varies massively from the mathematical average (in this case, around 50%).Good news for Capricorns and Cancers.

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