Blood type ab is the rarest blood type, occurring in only 4% of the population in the united states. in australia, only 1.5% of the population has blood type ab. suppose a random sample of 50 u. s. residents and 40 australians is obtained. consider the random variables described below: x: the number of us residents (out of 50) with blood type ab. y: the number of australians (out of 40) with blood type ab. z: the total number of individuals (out of 90) with blood type ab. which of the following is true about the random variables x, y, and z? check all that apply. x is a binomial random variable with n = 50 and p = 0.04  y is a binomial random variable with n = 40 and p = 0.015  z is a binomial random variable with n = 90 and p = 0.055