Probability problem for statisticians/mathematicians

[Advocate]

I think you could look at it as NASA having a 2% success rate at creating large fireworks!

[Bagpuss]

Tosh - by that rational the 300th flight is almost 100% fail. What happens if it does not?




There lies, dam lies, and statistics....

Don't blame Statistics, blame people's misunderstanding. Including your own to some extent.

[BrilloPad]

Tosh - by that rational the 300th flight is almost 100% fail. What happens if it does not?




There lies, dam lies, and statistics....

After 299 successful missions the chance of failure on number 300 is still 2%. But the chance of 300 successful missions is 0.2%.

Stats is such a wonderful thing.

[TimberWolf]

Okay, say there are 10 missions and a 0.2 probability of a failure overall, i.e. 2 in 10 of the missions will fail. You are 'allowed' to choose which one of the 10 flights you go on before any set off , but just after you choose, an omnipotent being with a beard rises out from the firmament and booms "Son of Abraham, Isaac and Jacob, listen upeth, mission 10 willeth defo faileth. In lightesth of thiseth insideth knowledge do thou wisheth to changeth your mindeth about whicheth misssioneth thou choseth afteralleth?"

Do you sticketh with the one you originally chose, or pick another mission?

The above is a fictional scenario and any resemblance to actual places, persons or supernatural beings whether living or dead or in some state not yet recognisable is not entirely coincidental.

[scooterscot]

After 299 successful missions the chance of failure on number 300 is still 2%. But the chance of 300 successful missions is 0.2%.

Stats is such a wonderful thing.

I stand corrected...

[NickFitz]

Okay, say there are 10 missions and a 0.2 probability of a failure overall, i.e. 2 in 10 of the missions will fail. You are 'allowed' to choose which one of the 10 flights you go on before any set off , but just after you choose, an omnipotent being with a beard rises out from the firmament and booms "Son of Abraham, Isaac and Jacob, listen upeth, mission 10 willeth defo faileth. In lightesth of thiseth insideth knowledge do thou wisheth to changeth your mindeth about whicheth misssioneth thou choseth afteralleth?"

Do you sticketh with the one you originally chose, or pick another mission?

Are you by any chance trying to drag the whole "two doors conceal goats, one conceals a car" scenario into the discussion?

I always wonder how they got the goats to keep quiet and stand still under the TV studio lights, but that's a different question. As is yours.

[expat]

Okay, say there are 10 missions and a 0.2 probability of a failure overall, i.e. 2 in 10 of the missions will fail. You are 'allowed' to choose which one of the 10 flights you go on before any set off , but just after you choose, an omnipotent being with a beard rises out from the firmament and booms "Son of Abraham, Isaac and Jacob, listen upeth, mission 10 willeth defo faileth. In lightesth of thiseth insideth knowledge do thou wisheth to changeth your mindeth about whicheth misssioneth thou choseth afteralleth?"

Do you sticketh with the one you originally chose, or pick another mission?

The above is a fictional scenario and any resemblance to actual places, persons or supernatural beings whether living or dead or in some state not yet recognisable is not entirely coincidental.

These 2 are not at all the same thing. That is where your scenario differs from the goats and the doors.

If the number that will fail is fixed, then it makes sense to change your choice after 1 failure other than yours is announced; but if the probablility is an independednt probability on each action, it doesn't matter whether you change or not.

This confusion in the other direction is why most people find it hard to analyse the goats/doors problem.

[BrilloPad]

Okay, say there are 10 missions and a 0.2 probability of a failure overall, i.e. 2 in 10 of the missions will fail. You are 'allowed' to choose which one of the 10 flights you go on before any set off , but just after you choose, an omnipotent being with a beard rises out from the firmament and booms "Son of Abraham, Isaac and Jacob, listen upeth, mission 10 willeth defo faileth. In lightesth of thiseth insideth knowledge do thou wisheth to changeth your mindeth about whicheth misssioneth thou choseth afteralleth?"

Do you sticketh with the one you originally chose, or pick another mission?

The above is a fictional scenario and any resemblance to actual places, persons or supernatural beings whether living or dead or in some state not yet recognisable is not entirely coincidental.

If I had picked mission 10 I would definetly switch. Probably.

[BrilloPad]

These 2 are not at all the same thing. That is where your scenario differs from the goats and the doors.

If the number that will fail is fixed, then it makes sense to change your choice after 1 failure other than yours is announced; but if the probablility is an independednt probability on each action, it doesn't matter whether you change or not.

This confusion in the other direction is why most people find it hard to analyse the goats/doors problem.

Isn't this more akin to a poisson distribution where the expected number of failures is 2?

So the probability of k failures is power(2, k) * power(e, -2) / k! ??

[Diver]

As a wise man once said:

A thousand probabilities does not make one fact