Saturday, June 18, 2011

PC Show 2011 - Unfair lucky draw

There are ten balls numbered from 0 to 9. Let us consider an event whereby you pick two balls successively without putting back the first ball. The probability of getting two balls in running order is 1/10 * 2/9 = 0.0222. What I meant by running order is for example if you pick a ball numbered 3 first, then the next ball must be numbered 2 or 4. When there are more numbered balls, the probability becomes much smaller if you must pick two balls in running order.

Now let us look at the lucky draw results of PC Show 2011. Can the organiser explain how in this world could they manage to pick up a number of tickets which are in running order? Maybe two tickets in running order are not too bad. But look at the 47th, 48th and 49th places?! It goes to show that the tickets were not drawn independently and some of the tickets were still attached to each other when drawn. Thus there is a high probability that some winners won double prizes and at least one winner won triple prizes.


not fair pcshow said...

Agree!!! it's not fair at all
I think they pick up the lucky slips. But the problem is they did not shake up the lucky slips in the box well.

For all you know, either the organiser is lazy and just pick up a stack and pass to the typist.

They should have a auditor for this !!

fly said...

I didn't even know there is a lucky draw. Where to get a ticket and how to participate?

Mike Dirnt said...

They are just lazy bumps!

fly its a waste you didnt register for the draw. You need to collect your lucky draw tickets at the 1st floor together with your receipt as proof. Every $50 entitles you for 1 lucky draw ticket. It is too late to collect now.

verbatin said...

this reminds me of IPOs in the early 1990s where there are no electronic payment. all were done by manual form.

I remb one of the IPOs which were very quite hot. that company is A-Sonic. 5 of my family applied for it. and 5 of us got it when the chances of being successful were like 10-15%.

apparently, they juz picked up the stack of the IPOs form and that's it.

Verbatin said...

correction. the stock is not A-Sonic. I think the name is Singapore Aerospace. This stock has been delisted if i remb correctly

Mike Dirnt said...


Prob(2 balls picked in running order) = 0.0222 * 10 = 0.222

what i calculated is the Prob of getting the 1st ball = 3 then the 2nd ball = 2 or 4.

Mike Dirnt said...

verb maybe they pick your family because they like the surname :P