"x objects are selected at random" (1 Viewer)

[emilios]

When they say for example, "4 fish are selected at random from a tank", how do I know if they're being selected one by one or all four at once?

I'm referring in particular to this q:



they solution to the first part is:

p(no tagged fish) = 50/60 * 49/59 * ... and so on

is there an alternate method of doing this q?

 

[mreditor16]

the key words are "placed together". this implies they were drawn one by one.

 

[mreditor16]

but imo it's ambiguous wording so dw bout it

 

[braintic]

When they say for example, "4 fish are selected at random from a tank", how do I know if they're being selected one by one or all four at once?

I'm referring in particular to this q:

View attachment 31202

they solution to the first part is:

p(no tagged fish) = 50/60 * 49/59 * ... and so on

is there an alternate method of doing this q?

It doesn't make any difference at all.

 

[emilios]

Had a brainfart lol (dont blame me I had chem). 50C4 / 60C4 yields the same answer.

That was a hsc q (1998 paper) so it better not be that ambiguous tomorrow!

 

[emilios]

It doesn't make any difference at all.

Thats strange and not very intuitive...

 

[braintic]

Thats strange and not very intuitive...

If you are selecting 4 fish, why would it matter whether you select them at one second intervals, one millisecond intervals, one nanosecond intervals or .... at the same time (0 second intervals)?