The discussion revolves around calculating the probability for a discrete random variable defined by a probability density function (p.d.f.) with specific values and a constant. The original poster seeks assistance in determining the probability P(1 < X ≤ 3.5) based on the given p.d.f.
Participants are exploring different interpretations of the problem, with some expressing confusion about the application of the p.d.f. and the constraints of the discrete random variable. There is no explicit consensus, but guidance has been offered regarding the nature of the variable.
Some participants note constraints related to the course requirements, such as the prohibition of calculus methods, which may affect the approaches discussed. Additionally, there is mention of a lack of examples provided in class, contributing to the confusion.
X is discrete. It can only take on integer values 1, 2, 3, 4. You are violating this condition in your calculation.bethanyd said:Homework Statement
If X is a discrete random variable with p.d.f. f(x) = {cx if x=1,2,3,4 ; 0 otherwise} where c is a constant.
Find P(1< X =< 3.5)
Homework Equations
I solved for c:
f(x) = 1 = c(1+2+3+4)
10c = 1
c = 1/10
The Attempt at a Solution
I have the following solution:
P(1< X =< 3.5) = f(3.5) - f(1)
= c(3.5) - c(1)
= c(2.5)
=0.25
I am not sure if this is correct. Please help!
Beth