Probability
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Discussion

Rex Ironstone

Original Poster:

1,130 posts

219 months

Monday 2nd November 2009
quotequote all
I've just had a heated arguement with my boss (not unusual) about probability and odds.
We were deciding how to draw out our office sweep for tomorrows Melbourne cup.
I said we might as well just list our names and draw out a horse in turn. He said no that wouldn't be fair on the person going last and we must pick a person at random and a horse at random. I fail to see how the odds of any position drawing out any paticular horse can differ. Surely the odds of the last horse being drawn out being the favourite is the same as the odds of the first horse drawn out. Their logic is that the first pick has equal probability of drawing out anyone of the possible options where last pick has no option for their pick and the odds are very high that the favourite. Lets call it horse A has already been picked so you have 0 chance of picking it. Surely thats just the randomness of the drawer. Apparently I'm a dumbass for not understanding this as to me before anything is drawn out horse A has the same probibility of being drawn out first as it does last.

Please Explain.

randlemarcus

13,646 posts

260 months

Monday 2nd November 2009
quotequote all
This is more about Perception than Probability.

Randomising the order in which people choose the nags prevents the draw being seen to have been slanted by those organising the thing in the first place.

Those who lose will grumble, fact of life.

Stevenj214

4,941 posts

257 months

Monday 2nd November 2009
quotequote all
You're correct.

Think of it as everyone picking one and opening it at the same time - each has an equal chance of picking the favourite. Doing it one by one simply elongates the process.

Rex Ironstone

Original Poster:

1,130 posts

219 months

Monday 2nd November 2009
quotequote all
Stevenj214 said:
You're correct.

Think of it as everyone picking one and opening it at the same time - each has an equal chance of picking the favourite. Doing it one by one simply elongates the process.
Well that's my arguement. this has been going on for over an hour and I'm really frustrated that I'm either a dumbass or maybe just once right.

dickymint

29,079 posts

287 months

Monday 2nd November 2009
quotequote all
Sod the sweep - lump your dough on Roman Emperor and Viewed to come second thumbup