document.write( "Question 1034553: Suppose that the random variable Y has probability distribution given by: \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "y p(y)
\n" ); document.write( "-2 0.11
\n" ); document.write( "0 0.32
\n" ); document.write( "3 0.57 \r
\n" ); document.write( "\n" ); document.write( " Find the mean, variance, and standard deviation of Y .
\n" ); document.write( "μ Y =
\n" ); document.write( "σ 2 Y =
\n" ); document.write( "σ Y =
\n" ); document.write( " What is the probability that Y is between μ Y −3σ Y and μ Y +3σ Y ? You may find it helpful to draw a probability histogram and mark μ Y , μ Y −3σ Y , and μ Y +3σ Y .
\n" ); document.write( "P(μ Y −3σ Y \n" ); document.write( "

Algebra.Com's Answer #649444 by robertb(5830)\"\" \"About 
You can put this solution on YOUR website!
\"E%28Y%29+=+mu%5BY%5D+=+-2%2A0.11+%2B+0%2A0.32+%2B+3%2A0.57++=+1.49\".\r
\n" ); document.write( "\n" ); document.write( "Now \"E%28Y%5E2%29+=+%28-2%29%5E2%2A0.11+%2B+0%5E2%2A0.32+%2B+3%5E2%2A0.57++=+5.57\"\r
\n" ); document.write( "\n" ); document.write( "\"%28sigma%29%5E2%5BY%5D+=+E%28Y%5E2%29+-++%28mu%5BY%5D%29%5E2+=+5.57+-+1.49%5E2+=+3.3499\"\r
\n" ); document.write( "\n" ); document.write( "==> \"sigma%5BY%5D+=+sqrt%283.3499%29+=+1.83\", to three significant figures
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" );