Two genes' expression values follow a bivariate normal distribution. Let X and Y denote their expression values respectively. Also assume that X has mean 9 and variance 3; Y has mean 10 and variance 5; and the covariance between X and Y is 2 . In a trial, 50 independent measurements of the expression values of the two genes are collected, and denoted as (X,, Y,), ..., (Xso, Yso) . We wish to find the probability P(X +0.5