Question

the principal will randomly choose 6 students from a large school to represent the school in a newspaper photograph. the probability that a chose student is an athlete is 30%. (assume that this doesn't change) What is the probability that 4 athletes are chosen?

Answer 1

Is this for a statistics class, or something like algebra?

Answer 2

Algebra 2

Answer 3

YTheManifold: that's not actually correct because you're not including the degree of freedom that any 4 can be chosen

Answer 4

Would you like to see what the possible answers could be?

Answer 5

Sorry \[ {6\choose 4}\cdot 0.3^4\cdot 0.7^2 \] of course

Answer 6

.3^4 * .7^2 is the p^k and p^(n-k) but you need the (6 choose 4) as well.

Answer 7

the formula YTheManifold just posted is correct - can you compute that, jesusfreak?

Answer 8

yes - this a Binomial Probability distribution

Answer 9

the general form is

(n choose k) * p^k * p^(n-k).

(typo in the previous one)

Answer 10

It all looks like gibberish. I have no idea what to do.

Answer 11

The answers it gives is 0.05, 0.06, 0.07, 0.08

Answer 12

OK, let's go through it step by step. Do you know how to compute .3^4?

Answer 13

th 6
4 part means the number combinations of 4 from 6

Answer 14

Yeah it's 81

Answer 15

You forgot the decimal -- it's 0.3^4 we're computing.
Then multiply that by 0.7^2.

Answer 16

ok it equals .003969

Answer 17

yes! Now you just need to multiply that by the (6 4) part, and you'll be done. That's called a "binomial". It's pronounced "6 choose 4", which means, if you have 6 things, how many ways can you choose 4 of them?

Answer 18

There's a formula for computing that, but a lot of people just type it into a calculator - it's 15 in this case.

Answer 19

The formula is n! / ( k! * (n-k)! )

Answer 20

Anyway so in this case just multiply 15 * .3^4 * .7^2 and that's your answer.