Geometric Distribution: Finding Specific p Value for Mean Calculation

[umzung]

Homework Statement

The number of items bought by each customer entering a bookshop is a random variable X that has a geometric distribution starting at 0 with mean 0.6.
Find the value of the parameter p of the geometric distribution, and hence write down the probability generating function of X.

Relevant Equations

$$q/(1-ps)$$

I know the p.g.f. of X is $$q/(1-ps)$$ and that the mean is $$p/q$$, but how do I find a specific value for p here?

 

[PeroK]

Homework Statement:: The number of items bought by each customer entering a bookshop is a random variable X that has a geometric distribution starting at 0 with mean 0.6.
Find the value of the parameter p of the geometric distribution, and hence write down the probability generating function of X.
Homework Equations:: $$q/(1-ps)$$

I know the p.g.f. of X is $$q/(1-ps)$$ and that the mean is $$p/q$$, but how do I find a specific value for p here?

What are $p, q$ and $s$ here?

 

[umzung]

What are $p, q$ and $s$ here?

$$p$$ is the probability, $$q$$ is (1 - probability) and $$s$$ is a dummy variable, not a random variable.

 

[PeroK]

$$p$$ is the probability, $$q$$ is (1 - probability) and $$s$$ is a dummy variable, not a random variable.

Okay, so the mean is $q/p = (1-p)/p$. Do you know the mean in this case?

 

[umzung]

Got it, thanks.