Suppose you are planning to study the respiratory physiology of the common toado, Tetractenos hamiltoni, a small fish found in tidal pools. Unknown to you, the pool from which you decide to collect specimens has 25 individual, 5 of which have a fungal infection in their gills that may confound the experiment you plan to run. What is the probability that
a) You collect 10 fish from this pool and none have infected gills?
b) You collect 10 fish and half have infected gills

Question

Suppose you are planning to study the respiratory physiology of the common toado, Tetractenos hamiltoni, a small fish found in tidal pools. Unknown to you, the pool from which you decide to collect specimens has 25 individual, 5 of which have a fungal infection in their gills that may confound the experiment you plan to run. What is the probability that 
a) You collect 10 fish from this pool and none have infected gills?
b) You collect 10 fish and half have infected gills

caozeyuan · Answer

@Loser66

caozeyuan · Answer

are we suppose to use binomial distribution? cuz I got wrong using it?

loser66 · Answer

I think we have to use conditional distribution

caozeyuan · Answer

ok, how so?

loser66 · Answer

I am not good at statistics, but let's try

loser66 · Answer

out of 25 fishes, 5 infected, hence probability of infection is 1/5 , hence P(non-infection) = 4/5

loser66 · Answer

@mathmale

caozeyuan · Answer

I made a table, does it help in anyway?

loser66 · Answer

Let's wait for expert. I don't know. I am sorry.

caozeyuan · Answer

This is too much for my peanut sized brain LOL

loser66 · Answer

hahaha... same as my brain on this topic.

caozeyuan · Answer

Guess I have to go to sleep now and see if I can dream a answer out

loser66 · Answer

go to bed!! forget it.

caozeyuan · Answer

@ganeshie8 any idea?

caozeyuan · Answer

@ganeshie8