to ask if you can answer a question re probability (Maths question)

[Fainne]

So, say I have 20 cards in a pack.

I pick one. It's the Ace of Diamonds let's say for argument's sake.

I then pick another one out of the same pack of 20 cards the following day.

Am I correct in saying that the odds of me picking the same card is a multiple of the single odds?

So 1/20 x 1/20 = 1/400

?

Because I've someone telling me the odds are still 1/20 that I'll pull the same card.

[mummmy2017]

The landlord gets to choose which shows the betting is on, so no he does not have to choose a show that is anything but a clear cut case. Again splitting hairs to try to make your answer the right one.

One show only. I will keep my door, the loaded door can still lose.
Many shows swap everytimes as 100 show I'd win about 66 times.

[mummmy2017]

You will always lose the race.
But if your putting 1,000,000 pounds bet on that you will beat Mr Bolt pony up the money.
Run honey run.
By the way Mr Bolt agreed not to win he is getting 3/4 of the pot.

[mummmy2017]

Sorry that your going to lose not win....

[BadLad]

"No the longer you win [a coin toss] the more likely it is that the next time you will lose."

Anyone still holding this as true?

[OffToTheMoon]

One show only. I will keep my door, the loaded door can still lose.
I've just won my bet.

[Lweji]

Dependent means that the chances of you winning or not depends on the result of the previous game.
Example: if you can only win if the previous game was a win too. Or if your chances of winning are higher if the last game was a win.

The odds of a chain are taken before any event of the chain happening. If you calculate the odds of 10 in a row after 5 wins, then the odds are different: only 1/2x1/2x1/2x1/2x1/2=1/32, because the five previous results are already known.

They are still independent events.

[mummmy2017]

Who cares if you won, that I stick, it's in black and white about twenty times on this thread.

[Lweji]

One show only. I will keep my door, the loaded door can still lose.

What if there was a 1/10 chance of you winning? Would you still keep the same door?
Why would you rather have a 1/3 chance of winning vs 2/3 chance in one game?

[Lweji]

And FGS, YOU'RE.

[mummmy2017]

But the result is not.
A chain of wins is only possible if all win.

[mummmy2017]

If your playing a winner stays on can you lose and still progress.

[whatsthecomingoverthehill]

This has all got a bit repetitive, so just to go back to an earlier post, that I don't think anyone answered:

A punter has one go on every Saturday’s lottery, picking the same numbers each week based on the day and month of the family’s birthdays. Would the following strategies increase, decrease or make no difference to the punter’s chance of winning the Jackpot.
1. Pick a better spread of numbers as birthdays do not include numbers over 31, and at least 3 of the punter’s numbers must be below 13.
2. Have a lucky dip instead.
3. Pick the numbers that have been drawn out the most over the previous two years.
4. Pick the numbers that have been drawn out the least over the previous two years.
5. Pick consecutive numbers. (eg. 11,12,13,14 etc.)
6. Pick the same numbers that were drawn last week.
7. Use a random number generator.
and for advanced students:
8. Do not enter for 51 weeks then have 52 lucky dips in one draw at the end of the year.

1 to 7 all make no difference to the odds.

8 is the interesting one. If you can guarantee that the 52 lucky dips are all different then you have a better chance of winning. But that doesn't necessarily tell you what the best strategy is. For instance, playing every week, you could win on the first week, and so don't have to play any more, saving 51 entries. Or if you do play every week then you have a chance of winning more than once.

I think that if the 52 lucky dips you buy are independent, so in theory you could have more than one the same, then it makes no difference to playing every week.

Easy way to think of it is if there are only 52 numbers to be picked from. The chance of winning at least once over the year when playing every week is:
[1-(51/52)^52] = 0.64

If you just play once and buy every number that could come up then you are obviously guaranteed to win.

[Lweji]

A chain of wins is only possible if all win.

But each result is independent of the others happening.
And the odds for the chain change (increase) as the result is known, but the odds of the next result is still the same as for every throw. Because the result for each throw is not dependent on the previous one.

YOU'RE showing YOUR lack of knowledge about what dependent means.

[Lweji]

If you've won the top prize in a lottery, are you better off keeping or changing your winning numbers, if you want to keep playing?

[mummmy2017]

You place the Bet before the event .
You have no knowledge of the result.
Strange that, maybe it is why you fail to see my point.

[chomalungma]

Anyone who places a bet with no knowledge of the event but knowing it is win or lose is an idiot

[mummmy2017]

If your trying to win a second time in a row , you can't have lost the first time.
If you can progress depends on the 1st result.

[Lweji]

You place the Bet before the event. You have no knowledge of the result.

If you mean the chain of coin tosses, that's why the odds are defined as multiples of the odds of each event, which is independent of every other. The odds would be different from 1/2x the number of tosses, if the results were dependent on the previous ones.

Of course, having a chain depends on having all results the same in a row, by definition, but it doesn't make one event dependent on any other.
But you wrote:
Winning ten games in a row means the answer depends on each of the 9 shows before being won....Or your chain of wins falls.
In this case, the odds of having a 10 chain would be 1/2 (funnily enough still the same odds of the single event, with or without chain), because you already know the previous results. But that's because of knowledge, not dependency.

[Lweji]

If your trying to win a second time in a row , you can't have lost the first time. If you can progress depends on the 1st result.

In this case you're not betting before you know the results of the two tosses, then.

[mummmy2017]

Many people place bets with only a win , lose outcome.
It's a bit controlling of you to say it can't happen because you don't like it.

[chomalungma]

Started a new thread. Can someone link to it

[Lweji]

Many people place bets with only a win , lose outcome.

Many people are idiots and lose a lot of money.

[Lweji]

www.mumsnet.com/Talk/am_i_being_unreasonable/3806651-Probability-thread-part-II-what-are-the-odds

[mummmy2017]

If your trying to win a second time in a row , you can't have lost the first time. If you can progress depends on the 1st result.

In this case you're not betting before you know the results of the two tosses, then.
What?
Bet. See If you can toss heads twice in a row.
Not oh look you got a heads can you do it again.