apparently, according to a paper mark scheme

Anyway im interested in

is a valid probability density function

But if you put the upper limit 2 in you get 2 out, when probability ranges between 0 and 1.

Thanks

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- May 31st 2009, 04:10 AMthomas49thChecking a continous random variable distrubtion
apparently, according to a paper mark scheme

Anyway im interested in

is a valid probability density function

But if you put the upper limit 2 in you get 2 out, when probability ranges between 0 and 1.

Thanks - May 31st 2009, 04:22 AMmr fantastic
- May 31st 2009, 04:45 AMthomas49th
I thought a PDF tells you what the probability is for a certain value you put in.

My PDF says that between 1 and 2 the probabilty of getting a value inbetween this is

where y is the value you want to find the probability of getting it

BUT if you put a 2 in you get a probability greater than 1, which cant be

Right?

Thanks - May 31st 2009, 04:49 AMMoo
Hello,

I think you're misunderstanding the role of the pdf :)

Two things :

- the probability that a continuous random variable takes a specific value is 0.

- if X has the pdf f, then :

, and not something like (Wink)

A third thing... :

A function is a pdf if : it is a positive function, and its integral over is 1. - May 31st 2009, 04:51 AMmr fantastic
You have many wrong ideas.

1. If Y is a continuous random variable, then Pr(Y = a) = 0. It only makes sense to talk about the probabilty that Y lies between two values.**You do not calculate probabilities by substituting values of y into the pdf.**

2. For , .

You are strongly advised to extensively review all you have learned on continuous random variables and probability density functions.