SOLUTION: I am not getting probability at all or where to start. It says "The following histograms each represent binomial distributions. Each distribution has the same number of trials n b

Algebra ->  Probability-and-statistics -> SOLUTION: I am not getting probability at all or where to start. It says "The following histograms each represent binomial distributions. Each distribution has the same number of trials n b      Log On


   



Question 1037650: I am not getting probability at all or where to start.
It says "The following histograms each represent binomial distributions. Each distribution has the same number of trials n but different probabilities of success p." It lists three graphs P(x). and has a probability formula of P(x)=nCxp^xq^n-x
And it says match p=0.3, p=0.5, p=0.6 with the correct graph.
Where do I start?

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
nCx and c(n,x) mean the same thing.
they are the combination formula that tells you how many sets of x out of n you can get where order doesn't matter.

the formula for nCx or c(n,x) is n! / (x! * (n-x)!)

the formula for the probability of x successes out of n possibilities is:

p(x) = c(n,x) * p^x * q^(n-x)

p(x) is the probability of x successes.
c(n,x) is the combination formula of how many sets of x you can get out of n possible choices.
p^x is the probability of success raised to the power of x.
q is the probability of failure raised to the power of (n-x).

q is equal to 1 - p.

when p = .3, q = .7
when p = .5, q = .5
when p = .6, q = .4

not being able to see the graphs, i'm not exactly sure what you are looking at.

the mean is usually n*p
the standard deviation is usually sqrt(n*p*q)
the variance is usually the square of the standard deviation = n*p*q

if you can send me a picture of the graphs and possibly the complete wording of the problem i might be able to figure it out.