Originally Posted by
jwells1999 First of all I just wanted to say sorry for the double post, I didnt know where to post my question.
As with the problem...
I was taught a different formula and I think thats what is getting me confused.
I was taught f(x)=n!/x!(n-x)!*p^x(1-p)^n-x
Mr F says: $\displaystyle \frac{n!}{x! (n - x)!}$ is the same as $\displaystyle {^nC_x}$. In fact, it's the basic formula for $\displaystyle {^nC_x}$
For a and c I got the following result
a)F(x)=5040/144*.064(.6)^4
F(x)=35*.064*.1296
F(x)=35*.0082944
F(x)=.290304 or 29.03%
c)F(x)=(7!) / (2!(7-2)! * (.4^2)(.6)^5
F(x)=[5040/240]*.16(.07776)
F(x)=21*.0124416
F(x)=.2612736 or 26.13%
but I cant figure out b. Should I be solving whereas x=6 since the problem is x>5?? Mr F says: read what I posted for this question.
If so I would get
F(x)=(7!) / (6!)(7-6)! *.4^6(1-.4)^7-6
F(x)=(7)*.004096(.6)
F(x)=7*.0024576 or .25%
but Im not sure if thats the right way to do it.
Any help would be much appreciated
Thanks