Wikipedia:Reference desk/Archives/Miscellaneous/2017 December 6

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December 6

Birthday

Why does it show two different birthdays for Florence Lake? Thanks — Preceding unsigned comment added by George W. Meyer (talk • contribs) 01:03, 6 December 2017 (UTC)

The Find a Grave photo of her gravestone shows November 27 (despite the entry also claiming January 1 at the top of the page). Clarityfiend (talk) 02:00, 6 December 2017 (UTC)

Gravestones are a good guideline, but they are not gospel. The date was posted in Wikipedia a couple of months after the Findagrave writeup was created.[1] The user who added that info has been blocked for the last couple of years, for copyright violation, which might tell you something. Looking at newspapers.com (a pay site), the obits that I'm seeing don't list a birthdate. Given the choice of the date on the headstone and the uncited date at the top of the Findagrave page, I would go with the headstone. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:48, 6 December 2017 (UTC)

Note that the Wikipedia edit does not mention Findagrave but does mention IMDb which, along with numerous other sources, gives the correct birthdate. Bugs correctly points out that gravestones can be unreliable sources, as was mentioned here:

According to our article, James Otis Jr was older than his brother Joseph. Both Wikipedia and Encyclopaedia Britannica give his birth date as 5 February 1725, which would have been recorded on his birth certificate as 1724 or 1724/5. He died on 23 May 1783 at 58. Joseph was born on 22 February 1725 "Old Style" according to the tombstone, which suggests that that (or 1725/6) was recorded on his birth certificate. Thus his year of birth would have been 1726 according to us. No way could James have been born in what we would call 1724. Joseph's tombstone mentions that he died on Sunday, 21 September 1810 at the age of 85 years and six months. That appears to me to be a mechanical conversion, and that he was actually 84 when he died. In any event, the tombstone may not be contemporary - 21 September 1810 was not Sunday in either old or new style.

– 62.30 21 November 2016.

Random devices, e.g. coin and dice.

A coin is a manual random device for two random options. The same is true for a dice, but for six random options. Is there a manual random device for three random options? What about four? HOTmag (talk) 14:31, 6 December 2017 (UTC)

d3

A six-sided die, repainted. Or a six-sided die rolled, then counted modulo 3.

d4

a tetrahedron - although these are hard to roll, as they're quite easily "thrown" by a skilled player to give a particular number. Games that need a lot of dice often use a dice tower to drop them down and roll them automatically and fairly. d4 can also be emulated by a d8 (a pair of square-based pyramids), but these should be numbered on both sides, as again they're easy to force onto one side or the other. Andy Dingley (talk) 14:36, 6 December 2017 (UTC)

here are some alternate designs for d3 dice. --Jayron32 14:45, 6 December 2017 (UTC)

Two coins give four outcomes. Gandalf61 (talk) 15:11, 6 December 2017 (UTC)

Ignoring the one or two zeros, a roulette wheel can be used for both the above scenarios and many more besides:

• Taking three equal groups of twelve numbers gives modulo 3
• Taking four equal groups of nine numbers gives modulo 4 — Preceding unsigned comment added by 92.8.221.62 (talk) 16:55, 6 December 2017 (UTC)

Our Dice#Variants lists them. 81.187.116.230 (talk) 19:09, 6 December 2017 (UTC)

I'm rather surprised that Wikipedia does not seem to have a general article on such things, which we could just have linked to here. This article would refer to

• Dice
• Coin tossing
• Spinners, either with spinning arrows on a fixed wheel or where the wheel itself spins, or other variations (as used in various sorts of games
• Standard playing cards and the specialized decks of cards used in other games
• Drawing lots, including lottery machines
• Use of a clock or stopwatch as a randomizing device
• Slot machines
• Pseudorandom number generators
• Hardware random number generators

I would have expected the lead sentence of dice to read something like "A die (also dice; plural dice) is a simple randomizing device consisint of a small throwable object with multiple resting positions..."; but not only does that article not link to Randomizing device, there is no such article. (Randomizer, the other obvious title, is not a red link, but it just redirects to a telecommunications scrambler.) Anyway, the most general simple randomizing device is a deck containing selected cards, or a spinner. Either one is easily constructed to randomly select one of N values for any reasonably small number N. --69.159.60.147 (talk) 19:41, 6 December 2017 (UTC)

You don't actually need a device to do this. You can draw up a randomisation plan and apply it to the last digit of the date on the coins in your purse. In the days when car registration numbers included a number up to 999 either at the beginning or the end you could apply the same technique looking at the numberplates of passing vehicles. You could open a book and note the number of the page which appears. The possibilities are endless. 92.27.49.50 (talk) 11:15, 7 December 2017 (UTC)

Do people even carry coins around anymore?--WaltCip (talk) 13:20, 7 December 2017 (UTC)

Congratulations, Walt, you fail the Turing test! Interesting to learn that at least one of our editors is not a person. μηδείς (talk) 16:00, 7 December 2017 (UTC)

Huh?--WaltCip (talk) 20:48, 8 December 2017 (UTC)

Silly wabbit. Humans still use coins, though pennies have gone the way of the dinosaur in my neck of the woods. Still, Walt could be an alien. Aliens are people too. Clarityfiend (talk) 11:19, 9 December 2017 (UTC)

If we restrict ourselves to dice, any even number n can be generated using a bipyramid with n sides (like the 16 sided die shown in the dice article). Any odd number m can be generated using either a bipyramid with 2m sides (with 2 faces for each number), or an m-gonal prism, with the ends shaped so they cannot be landed on. Some of these will result in edges facing upwards when the die is rolled, but that can still allow a number to be read with the right markings. MChesterMC (talk) 16:31, 7 December 2017 (UTC)

We had better not restrict ourselves to lists, since in any human generated list of numbers, a number beginning with the symbol 1 is anywhere up to 30% likely, if I remember correctly. This is an artifact of counting. Say there are three hundred items. One third of them will be numbered from 100-199. (likewise 10-19, if we don't count the leading zero.) So book pagination or selection of a finite number of countable objects is not a good way to randomize things.

Ah, a google search shows we have the relevant article, Benford's law, which agrees exactly with my recollection. μηδείς (talk) 21:48, 8 December 2017 (UTC)

If you're caught short, you still need to spend a penny. 92.27.49.50 (talk) 11:52, 9 December 2017 (UTC)

That's why I specified "the last digit". 92.27.49.50 (talk) 12:35, 9 December 2017 (UTC)

Your example of coins on hand was (I took) a very narrow one, with the only possible leading digits of 1 or 2 assuming the Gregorian Calendar. Even then, the last digits will not necessarily be random, given the length of circulation and the number of coins minted in a year, both of which vary non-regularly. In any case, your suggestion will approach randomness better than a leading digit sample, obviously. My post was a bit more general and explanatory. μηδείς (talk) 17:26, 10 December 2017 (UTC)

I read through this because I do a lot of work with PRNGs. I didn't see mention of tops. From 3 sides to many sides, a top is an effective random number generator. You spin it and it eventually settles on a side. Simply weight the tip to ensure it doesn't flip onto the top of the top. 209.149.113.5 (talk) 18:08, 11 December 2017 (UTC)

I've not seen tops with numbers on the side, however a few weeks ago a description of a device which would do the job was added to Perpetual calendar (check the last but one revision as it's not in the current version). Six and nine are rotations of a face of one of the two cubes so if that comes up treat as six. If 0 of that cube (the one which also has 6 on it) comes up treat as 9. If 1 or 2 of that cube comes up disregard the throw (because these numbers appear on both cubes) and throw again. As you are throwing two cubes but only one counts decide in advance which one that will be (e.g. the one which lands nearest to the left hand side of the table). 82.13.208.70 (talk) 18:15, 12 December 2017 (UTC)

Many cultures have had tops like the dreidel. Some have four sides. Some have three. Some have more then four. There is no reason that they cannot be numbered. 209.149.113.5 (talk) 18:25, 13 December 2017 (UTC)