2. 3 RANDOMVARIABLES o A random/stochastic variable(rv. for short):a variable whose (numerical) value is determined by the outcome of an experiment. (1)A discrete random variable --an rv. that takes on only a finite (or accountably infinite) number of values (2)A continuous random variable -=an rv that can take on any value in some interval of values2.3 RANDOM VARIABLES • A random/stochastic variable（r.v., for short）: a variable whose (numerical) value is determined by the outcome of an experiment. • （1）A discrete random variable—— an r.v. that takes on only a finite (or accountably infinite) number of values. • （2）A continuous random variable——an r.v. that can take on any value in some interval of values