[QUOTE=jasong;317820]but that 1952 days marks the point where there's a precisely 50/50 chance that a prime will already have been found, correct?[/QUOTE]

No. We often think in terms of a Normal Distribution, where the "middle" is the same regardless of whether we have in mind the mean, the median, the mode, or some other measure or centrality. But when you get away from symmetric probability distributions, these things no longer coincide.

The probability model used here is the exponential distribution if we think of it as continuous, or the geometric distibution if we think of it as chunked into daily increments. David gave the mean (what we usually mean when we say average). You are asking for the median.

[QUOTE=jasong;317820]I've never taken a statistics class, so please be kind, but that 1952 days marks the point where there's a precisely 50/50 chance that a prime will already have been found, correct?[/QUOTE]
You are not a million miles out:

I am saying that the probability of no new Mprimes before d days is

e[SUP]-d/1952[/SUP].

So probability of no prime for 1952 days is 1/e = 0.37

e[SUP]-d/1952[/SUP] = 1/2 when d = 1952 * 0.69 = 1353

David

Brief update. The following are our next closest predictions:

[CODE]ET [COLOR="Green"]12/20/2012[/COLOR]
ewmayer [COLOR="green"]45,000,000[/COLOR] <-originally posted in '06 before M47 was found.
wreck 49,000,000 [COLOR="green"]1/1/2013[/COLOR]
Dubslow 60,000,001 [COLOR="green"]1/1/2013[/COLOR]
Oddball 78,000,000 [COLOR="green"]1/1/2013[/COLOR][/CODE]

We are now 3.5 sigma beyond the average gap interval. (11/28/12). (Further along if the gap between in '08 is ignored.

My Virgin Ivy's very first LL will be PRIME!!!
 

Drum roll for assignment until I actually ask for one .... soon.

[QUOTE=petrw1;320665]Drum roll for assignment until I actually ask for one .... soon.[/QUOTE]

Almost forgot....

49532123 - January 12, 2013

[QUOTE=petrw1;322036]49532123 - January 12, 2013[/QUOTE]
Previously you predicted 55,555,543 would be found prime on 5/5/2012.

[QUOTE=Uncwilly;322037]Previously you predicted 55,555,543 would be found prime on 5/5/2012.[/QUOTE]

Even Kreskin misses on rare ocassions :smile:

And JB already LL'd it as Non-prime.

Did anyone compute a composite of the 'guesses' herein?
An average of the guesses, weighted or not?
I'm curious about which guesses come nearest these averages.

[QUOTE=petrw1;322036]Almost forgot....

49532123 - January 12, 2013[/QUOTE]

The date has come and gone, but the exponent hasn't...keeping fingers crossed...

Maybe when people post their guesses, they should post how they came up with the guess. This would be different from crank postings because people wouldn't be claiming how awesome their method is, just how they came up with their guesses. If the guess(es) are correct, then we can re-visit their method.

[QUOTE=davar55;324711]Did anyone compute a composite of the 'guesses' herein?
An average of the guesses, weighted or not?[/QUOTE]
I can do that, I have all the data stored away. I will get to it a little later.

Edit:
62,714,889 on7/21/2010 (for all semi-serious guesses, including those carried over from the previous Guess Mxx threads)
64,987,482 on 12/27/2011 (for only those guesses since our last discovery)