/sci/ - Science & Math

[Anonymous No.5230870]

Het guys could you help me whit this question?
We flip a fair coin three times. What is the probability that the first flip was "heads" given that two out of the three flips were "heads"?
would really appreciate it if you could :)

[Anonymous No.5230878]

Individually, 1/2.

Taken as a whole, the chance of getting heads three times is (1/2)³

[Anonymous No.5230880]

2/3

[Anonymous No.5230884]

>>5230880
>>5230878
could you please explain how you got that answe? :)

[None !!BJiYgff8zf2 No.5230896]

>>5230870
>>5230870

sauce on the gif plz ;)))

[Anonymous No.5230910]

6/11

[Anonymous No.5230918]

>>5230880
That's the chance that any one of the 3 are heads, not the first one.
>>5230878
That doesn't answer anything.

OP is fucked lol. /sci/ doesn't know shit.

[Anonymous No.5230923]

You guys need to learn to conditional probability.

3 possible outcomes:
HHT
HTH
THH

All of which are equally likely. In 2 of these, heads is first.

so, P(1st flip head | 2 heads) = 2/3.

[Anonymous No.5230927]

one outcome on one flip= 0.5
one outcome on three flips=0.5*0.5*0.5
* is the logical and operator
how many possible outcomes are there?

HTH
or
HHT

+ is the logical or operator

0.5*0.5*0.5 + 0.5*0.5*0.5

[Anonymous No.5230933]

>>5230918
>That's the chance that any one of the 3 are heads, not the first one.

Let X be heads and Y tails.

Possible results are:
XXY, XYX, YXX
First coin was heads in two situations out of three.

[Anonymous No.5230939]

>>5230927

Nope, this is the probability that the first flip is heads AND there are only two heads in total. Which is different to the probability that the first flip is a head GIVEN there are only two heads in total.

[Anonymous No.5230944]

50/50 breh. The others are already set in stone.