# Let the p.m.f. of M be defined by f(x)=x/8,x=1,3,4.

1. Aug 28, 2009

### morr485

Let the p.m.f. of M be defined by f(x)=x/8,x=1,3,4. What is the mean of M?
Is this the same an E(M) of a binomial?

2. Aug 28, 2009

### g_edgar

Re: p.m.f.

I guess we have P(M=1)=1/8, P(M=3)=3/8 and P(M=4) = 4/8. These add to 1.
So the mean is ... what? Do the computation from the definition.
Yes, this is another name for E(M), but it is not binomial.