求教一道统计学数学题.Suppose X and Y are random variables such that the atandard deviation of X is 2 and the standard deviation of Y is 5.Consider a random variable Z defined as Z=3X-2Y+5.问 a:Assume that X and Y are independtly distribute

求教一道统计学数学题.Suppose X and Y are random variables such that the atandard deviation of X is 2 and the standard deviation of Y is 5.Consider a random variable Z defined as Z=3X-2Y+5.问 a:Assume that X and Y are independtly distribute 求教一道数学题：化简 一道数学题求教 一道数学题,求教, 求教一道数学题 求教一道大学高等数学题! 求教一道微积分的数学题, 数学题统计学 统计学题目,求教. 求教一道线性代数的数学题如何解 SAT上的一道数学题求教(步骤) 一道数学题.求教.麻烦说详细点. 求教一道统计学数学题a fair coin is tossed twice.let X represent the number of heads obtained on the first toss and Y represent the total number of heads obtain in two tosses.a:derive the birvariate probability distribution for the variables 急.求教数学题一道8x{76x125}=?递等式计算,如能巧算的话,就巧算, 求教一道GRE数学题x is an integer greater than 1,比较3^(x+1)和4^x哪个大? 求教数学题用x解方程 求教一道不定积分 √x/(1+x) 一道数学题5x