What are your thoughts?A discrete r.v has pdf. Let n>1
p(x)= (2 x)/n(n+1) where x=1,2,..,n
find cdf
these standard formulas can be used
∑ x= n(n+1)/2
∑ x^2=(n(n+1)(2n+1))/6
Do you know the definitions of:A discrete r.v has pdf. Let n>1
p(x)= (2 x)/n(n+1) where x=1,2,..,n
find cdf
these standard formulas can be used
∑ x= n(n+1)/2
∑ x^2=(n(n+1)(2n+1))/6
The CDFI know what they all mean
but the thing that i can't get my head round is p(x)= (2 x)/n(n+1) where x=1,2,..,n
in this case p(x)=2x/n(n+1) where x=1,2,...,n CORRECT!
Come on, k is just an index. You want it to be x, then let it be x.Thank you pka but i'm more interested in the process than the answer itself.
For instance how did you get (k), shouldn't it be (x)
plus i don't understand your notations on the limits
Note that p is a function of x and not n. So what is p(1)? What is p(2)? .... Do you see some pattern?. So what is cdf(1), cdf(2),...,cdf(n)?I know what they all mean
but the thing that i can't get my head round is p(x)= (2 x)/n(n+1) where x=1,2,..,n
i don't know how to work with it.
I don't know if i'm making sense
but if i had for example a pmf p(x)=x/10 where x=1,2,3
i would be able to find the cdf
in this case p(x)=2x/n(n+1) where x=1,2,...,n
where do i start
Reading the above reply, I am lead to think that you have no idea about any of this.Thank you pka but i'm more interested in the process than the answer itself.
For instance how did you get (k), shouldn't it be (x)
plus i don't understand your notations on the limits
Reading the above reply, I am lead to think that you have no idea about any of this.
A CDF is a monotone increasing, right-continuous function that maps \(\displaystyle (-\infty,\infty)\to [0,1]\).
If the pdf is finite (as in this case), then its CDF is a finite step function.
That is exactly what I gave you. The fact that you even have to ask about the (k) in the sum, again tells me that you do not grasp the C (aCumulation) stands for in CDF.
You need to know what CDF means (it's just a definition) when it is 1st define, not at the end of the chapter. IMO never move on until you understand theorems and definitions. After all, you can't play the game unless you know the rules (theorems and definitions).I guess you're right,
hopefully by the end of the chapter i'll be able to understand it half as good as you.