The length of time required by students to completea 1 hour exam is a random variable with a density function given by

f(y)={cy^2+y, 0<y<1
{0 , elsewhere

a)find the value of c.
b)find the cumulative distribution F(y)
c)use F(y)in (b)to find F(-1),F(0),and F(1).

The length of time required by

students to completea 1 hour exam is a random variable with a density

function given by

f(y)=\left{\begin{array}{rcl} cy^{2}+y, \;\ 0<y<1\\0, \;\ \;\ \text{elsewhere}\end{array}


a)find the value of c.

Set up the integral:

\int_{0}^{1}[cy^{2}+y]dy

Integrate the definite integral, set your result equal to 1 and solve for c.

The total probability is equal to 1, so that is why we set the result equal to 1. Use this to answer the other parts of the problem.

My answer of c is 3/2,but actually how to going to solve the question (b) and (c)><i really depressed of it,can u show me the solution of this 2 question?thanks a lot about it!!

Anyone can help me solve the question b and c?? plssssssss!I really need the help