Reptile & Amphibian Forums

Just clearing something up for a friend...

Pastel male x fm spider = Bubble bee
Spider male x fm pastel = Bubble bee

So are you just as likely to get bubble bees either way?

I think you got your answer on the other forum...didn't ya??

im still trying

Yes you SHOULD get one.
odds
1 bee
1 normal
1 pastel
1 spider
They are the odds one in four.
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RicK @ BbI

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COurse that is one in four chances PER EGG, thus the actual results per clutch can be completely different than one of each per four eggs.
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PHLdyPayne

Nope. the 25% odds of hitting the bee could be on a two egg clutch or on a 12 egg clutch. The odds don't increase or decrease depending on how large the clutch is. 25% is 25% is 25%.
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www.strictlyballs.ca

You bet. Just like dice. Each roll you have the exact same odds of a seven or eight come out.
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RicK @ BbI

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My statistics professor was a hot Iranian lady but I did pay a little attention to the actual subject.

You can find the cumulative odds of independent events by multiplying the odds of each event together.

The existence and quick production of killer bee (homozygous pastel and het for spider) is a pretty good indication that spider and pastel are certainly separate genes and probably not linked at all - i.e. inherited independently.

So, each baby from pastel X spider has a 50% chance of getting the spider gene from the spider parent and an independent 50% chance of getting the pastel gene from the pastel parent. The cumulative chance of any one egg getting both genes to be a bumblebee is .5 X .5 = .25 (i.e. 25%).

When it comes to figuring the odds of producing at least one bumblebee in a clutch (i.e. hitting the bee) you can use a trick to make the equation much easier than figuring the odds of all the different ways you could produce one or more. The trick is to figure the odds of each egg not having a bee in it. If there is a 25% chance an egg being a bumblebee and we know it either is or isn't (i.e. 100% of the time it will either be a bumblebee or it will not be a bumblebee) we can figure the odds of it not being a bee as 100% - 25% = 75%. We can then figure the odds of being skunked as the odds of each egg not being a bumblebee multiplied times it's self the number of eggs. So, the odds of not producing any bumblebees in a 4 egg clutch from spider X pastel is .75 X .75 X .75 X .75 which can be written as .75^4 (to the 4th). That comes out to 31.6%. So, if the odds of not getting any bumblebees in a 4 egg clutch are 31.6% then the odds of getting 1 or more are 100% - 31.6% = 68.4%.

The general formula for getting one or more success is:

1 - (odds per chance of failure)^number of chances

So if you got an 8 egg clutch rather than a 4 egg clutch your odds of getting at least one bumblebee would be:

1 - (.75)^8 = 90%

By growing your female up to produce 8 eggs rather than 4 you increased your chance of producing a bumblebee from 68% to 90%.

However, note that you never get a 100% guarantee. If you bred that pair for 50 years and averaged 8 eggs a year to produce 400 eggs you would still have a very very small chance of missing
(.75)^400 = 1 X 10^50 or about a 1 in 94,513,673,485,239,612,814,977,642,791,352,000,000,000,000,000,000 chance of failure.

I was in AC at a craps table and saw a hard eight [two 4's] come up 5 times without a soft eight or a seven come up. A dollar bet would have paid you $100,000.00. [1, 10, 100, 10,000, 100,000] Would one ever make money playing that hard eight with a $300,000.00 bank roll? I doubt it. But it happens.
Craps to me is like odds in a clutch. Except a rolled number can not be infertile! LOL

25% is 25% in the long hall.

Here is one for ya.

My axanthic x het axanthic produced 8 eggs last year. 4 hets and 4 axanthics. Big deal average but add 2.2 hets and 2.2 axanthic the "perfect clutch."

The other two clutches were always less in the visible morph.
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RicK @ BbI

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Rick,

You are discussing two different types of probability results.

Your 25% is 25% in the long haul, is expected value of random variables.

Pick any egg out of the clutch; there is no way to know what is inside.

Open it, write down what it was, then pick another egg and continue the process.

When you have opened up a sufficiently large enough “sample” of eggs and averaged your results, you are left with the expected values. Your 25% bumblebee result.

Your percentage is based on the average outcome when interpreting data of “sufficiently large” samples of eggs.

Randy was talking about independent probability of random variables.

What is the probability of getting at least one bumblebee out of a clutch of a specific size.

While both are correct in what they are interpreting, your 25% is correct when held to the constraints of the large sample size. Where as independent probability places no limitations on the clutch size.

Did that muddy the waters more??
TomChambers

I understand what Randy was saying.
And in a six egg clutch you could still get all normals. Perhaps all eggs are bees too!
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RicK @ BbI

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sure you could, but thats the definition of probability, the likelihood of an event happening.

there are no guarantees with probability.

just a numerical likelihood.

TomChambers