can you solve this problem? probability question, please help

[zulu]

in lottery, there are 20 balls, only 8 comes out. what are the chances that one ball didn t go out for 19 times in a row? please help

 

[katxt]

One particular ball did not appear? or some ball did not appear?

 

[zulu]

One particular ball did not appear? or some ball did not appear?

the same ball didnt appear 19 times in a row..there are 20 balls and lets say ball number 5 didnt appear 19 times in a row

 

[katxt]

OK. So what is the probability that 5 didn't appear in the first draw?

 

[zulu]

I dont know

 

[zulu]

maybe 60% ?

 

[katxt]

Right. 12 chances of a miss out of 20 = 60% or 0.6.
The probability of 2 misses in a row is 60% of 60% = 0.36 = 0.6^2. Carry on the pattern.

 

[zulu]

I dont know how to calculate that long, can you do it for me,please

 

[katxt]

Do have a calculator? or find one on line.

 

[zulu]

I dont know how to find 60% of every number i get 19 times in a row..Can you please do it for me

 

[katxt]

No. What you need is 0.6^19. Google it. kat

 

[zulu]

0.00006093597 ?
So that means it will apear 6 times in 100 000 draws?

 

[katxt]

Well done,

 

[zulu]

well, you could told me solution right away thank you

 

[katxt]

But now you have learned something.

 

[Dason]

well, you could told me solution right away thank you

If that's your attitude you gotta pay.

Also keep in mind that is the probability *if* you specified a certain number that you didn't want to show up at all. It's a slightly different calculation if all you want is the probability that after 19 draws there exists at least one number that wasn't picked.

 

[zulu]

So I guess if I want to calculate on the same lottery(8/20) that the same ball will appear 11 times in a row i will 0.4^11 =0.00004194304 which means 4 times in 100 000 draws? am I right?

 

[zulu]

If that's your attitude you gotta pay.

Also keep in mind that is the probability *if* you specified a certain number that you didn't want to show up at all. It's a slightly different calculation if all you want is the probability that after 19 draws there exists at least one number that wasn't picked.

so it wont be the same result like certain number? what is than calculation for at least one number that wasnt picked 19 times in a row? it s definetly lower number than 6 times in 100 000

 

[hlsmith]

it s definetly lower number than 6 times in 100 000

why write this? give answer now!

 

[zulu]

why write this? give answer now!

my bad, is much higher