the comulative distribution :given by >>>>
F(x)=
0 x<=0
x\8 0<=x<4
x^2\16 2<=x<4
1 x>=4
find >>>>>>>>>
1-mean of (-2-3x)
2-p(1<x<3)
my solutions
1-mean = -41\4
2- p(1<x<3)= 1\4
The mean cannot be negative, the probability that $\displaystyle x$ is less than or equal $\displaystyle 0$ is $\displaystyle 0$.
You need to find the density $\displaystyle f(x)=F'(x)$ (you don't need to worry about this being undefined at a finite number of points) first then the mean will be:
$\displaystyle \int_{-\infty}^{\infty} x f(x)\ dx$
$\displaystyle p(1<x<3)=F(3)-F(1)=3/8-1/6=1/4$
RonL