# Math Help - Statistics and Geometric Progression

1. ## Statistics and Geometric Progression

Here is the problem:
Determine constant c so that c(1/4)^n, n = 1,2,3 ...
satisfies p.d.f for R.V. N.

So I state the geometric progression

Sn = ( 1 -r^n / 1 - r)

yielding

1/4 [ 1 - (1/4)^n / 1 - (1/4)]

Then I take the limit of the geometric progression and I get:

1/3

and I conclude 1 = 1/3c so c = 3

does this sound correct.

2. Hello,
Here is the problem:
Determine constant c so that c(1/4)^n, n = 1,2,3 ...
satisfies p.d.f for R.V. N.

So I state the geometric progression

Sn = r ( 1 -r^n / 1 - r) << if the sum starts from n=1

yielding

1/4 [ 1 - (1/4)^n / 1 - (1/4)]

Then I take the limit of the geometric progression and I get:

1/3

and I conclude 1 = 1/3c so c = 3

does this sound correct.
It's perfect, just be careful of the red thing