Probablity question (confused on the pdf)

  • Thread starter Thread starter bennyska
  • Start date Start date
  • Tags Tags
    Pdf
bennyska
Messages
110
Reaction score
0

Homework Statement

<br /> $f(x)=\begin{cases}<br /> 7(4)^{-i} &amp; x\in(\frac{1}{2^{i}},\frac{1}{2^{i-1}}],i=1,2,3,...\\<br /> 0 &amp; 0\geq x,x&gt;1<br /> \end{cases}$ (please excuse the poor latex)<br /> <h2>Homework Equations</h2><br /> <br /> <br /> <br /> <h2>The Attempt at a Solution</h2><br /> the problem I&#039;m having is say x=3/4. then according to the pdf, shouldn&#039;t P(x)=7*(4^-1)=7/4&gt;1. i mean, shouldn&#039;t it be bounded by 1? when i integrate this out, i get 1, like i should, so I&#039;m not sure what mistake I&#039;m making.
 
Physics news on Phys.org
what is the actual question? Maybe I'm missing it, but it seems like you just posted an equation without any description of what you are trying to do
 
Why do you expect that a pdf must be bounded by 1? Consider a random variable that is uniformly distributed over the interval [0, 1/2]. Is that pdf bounded by 1?
 
well, the actual problem is show that this function is a pdf. so i need to show that it integrates to 1, which it does, but i believe i also need to show that it's bounded by 0 and 1 for all x in the domain, which is the problem I'm having a hard time with.
 
oh, got it. duh. thank you.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top