What are the odds?

[GB]

Picked up a pack of 6 extra large eggs last week. I have used 5 and so far all 5 have been double yoked...what are the odds the 6th is also double yoked or have I missed something obvious in that all extra large eggs are always double yoked?

 

[flymo]

.....what are the odds the 6th is also double yoked

Evens. It is or it isn't.

 

[SS4]

It will be the chance of getting a double-yolk egg normally. Since the events are independent the previous five do not affect the chances of the sixth (for truly random selection of course). It's like tossing a coin - if you get 5 heads in a row there is still a 50% chance of getting a sixth head.

I'd not say it's evens though, if only because the chance of getting an double yolk with one pick is not one in two unless you've got some information the rest of us aren't privy to . In essence you may consider it equivalent to the chance of picking one egg from a choice of (n-5) eggs because of it's independence.


Perhaps the greengrocer('s wife/daughter) has a crush on you

 

[eastwestdivide]

Evens. It is or it isn't.

In that case, I think I'll do the lottery this weekend, 50:50 chance, either I'll win or I won't. Maybe buy two tickets just to make sure.

To answer the original question, maybe we need to know more about the incidence of double-yolkers generally, whether they occur more often in certain flocks, whether those flocks' eggs generally stay together on the production line. Perhaps the production process separates them by size, and double-yolkers tend to be larger, and so tend to get sorted together into the XL packs.

Any poultry farmers on here to help?

Sometimes the question's more interesting than the answer.

 

[GB]

I'm used to finding the odd double yoke in a pack of 6 but never more than 1.

Perhaps egg are separated by weight rather than physical size?

 

[michael769]

According to Google the odds of a double yolk is 1:1000. Google also reveals that young hens are more prone to doing this and that it does run in flocks (so must have a genetic component).

As others have pointed out the odds of any given egg having one, assuming random selection, is independent of any other so the fact that you have had 5 so far should not change the odds for the 6th which would remain 1:1000.

If the eggs were selected truly at random the odds of getting six eggs in a row would be 1000 to the power of 6 (One in quintillion) - but note these odds are independent of the individual odds that the 6th egg is a doubler.

Eggs are not selected at random though. They are grouped together first by farm and this increases the chances that all eggs came from the same hen, but also means that other hens are likely to be genetically similar and related to each other - this means that the hens that laid the eggs in the box may be from a stock that is prone to lay double yolked eggs so the odds of this flock laying such eggs will be better than 1:1000.

The eggs are also graded by weight and size - and this will probably group eggs with similar characteristics together. Another factor to consider is that it is possible to detect double yolks Waitrose at one point did sell boxes of double yolked eggs so selection of eggs is inherently biased

As the selection is biased - if you find one egg with a double yoke in a box the odds of another beign double are actually much better than 1:1000.

http://menmedia.co.uk/rochdaleobser...she-finds-29-double-yolkers-in-box-of-30-eggs

 

[Johnuk123]

I remember having a triple yolk egg about 3 years ago, they're not as rare as you might think.

 

[Oswyntail]

This is dealt with at http://www.bbc.co.uk/news/magazine-16118149

 

[GB]

Thanks for all the replies, and thanks for the link Oswyntail, makes interesting reading.

 

[IanD]

I get my eggs from a local farm and if the first egg picked at random from a tray of 30 is a double yolk then the chances are the majority of eggs are also double yolked. Once had a whole tray of 30.

The farmer reckons that some chickens are more inclined to lay double yolked eggs so if that is true then there is a high chance that your 6th egg will be double yolked if from the same source.

Could be just the farmer talking nonsense though.

 

[Johnuk123]

Could be just the farmer talking nonsense though.

Well it would certainly make a change from moaning about the weather.

 

[user15681]

This is where a Biology and Statistics A level come in handy.

1 in 1000. But, as said, once you find one you are likely to find others.

 

[Peter Mugridge]

I had a whole box of 10 eggs with double yolks once; they weren't the special packs marketed as such, but they were large eggs - I usually buy the "Big and Fresh" brand from Tescos - the ones in yellow wrapped boxes. They do seem to come up with double yolks fairly regularly; I reckon I get one double yolk for every five or six boxes of 10.