document.write( "Question 1027798: Q1
\n" ); document.write( "Suppose that the random variable X has the following cumulative distribution function:
\n" ); document.write( "x -1 1 3 5
\n" ); document.write( "F(x) 1/4 1/2 3/4 1\r
\n" ); document.write( "\n" ); document.write( " Find the probability distribution of this random variable.
\n" ); document.write( " Find p(x<3),p(x ≥1 )
\n" ); document.write( " Find the mean of the random variable X.
\n" ); document.write( " Find the standard deviation of the random variable X.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Q2 \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The cumulative distribution function of the random variable X is given by: \r
\n" ); document.write( "\n" ); document.write( "F(x)={0(1- 9/x^2 ) for3\n" ); document.write( "\n" ); document.write( " Find the probability density function for the random variable X.
\n" ); document.write( " compute p(X≤ 5) and p( 8< X )
\n" ); document.write( " Find the expected value for the random variable X. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #644388 by robertb(5830)\"\" \"About 
You can put this solution on YOUR website!
Q1
\n" ); document.write( "Suppose that the random variable X has the following cumulative distribution function:
\n" ); document.write( "x -1 1 3 5
\n" ); document.write( "F(x) 1/4 1/2 3/4 1
\n" ); document.write( "Find the probability distribution of this random variable.
\n" ); document.write( "Find p(x<3),p(x ≥1 )
\n" ); document.write( "Find the mean of the random variable X.
\n" ); document.write( "Find the standard deviation of the random variable X. \r
\n" ); document.write( "\n" ); document.write( "The pdf should be as follows:
\n" ); document.write( "x -1 1 3 5
\n" ); document.write( "p(x) 1/4 1/4 1/4 1/4
\n" ); document.write( "Hence it is discrete uniformly distributed.
\n" ); document.write( "p(x<3) = p(-1) + p(1) = 1/2, as can be directly read off from the table for F(x).
\n" ); document.write( "p(x ≥1) = 1 - 1/4 = 3/4, as can be read off again from the table for F(x).
\n" ); document.write( "Mean is \"E%28X%29+=+%28-1%2B1%2B3%2B5%29%2A%281%2F4%29+=+2\".
\n" ); document.write( "Variance is
\n" ); document.write( "==> \"SD%28X%29+=+sqrt%285%29+=+2.236\" approximately
\n" ); document.write( "
\n" ); document.write( "
\n" );