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formula quiz 8

random variable is a variable whose value is a numerical outcome of a random phenomenon. there are two types of random variables (discrete and continous)
a discrete random variable is a random variable which takes on only a finite or countable number of possible values
a probability distribution foa rv X tell sus what the possible values of X are and how porbabilites are assigned to those values (also called probability function)
a continous random variable x takes all values in an interval of numbers
mean of a random variable is x1p1+x2p2+xnpn
the variance of this random variable is sigma (xi-mu)squared pi
the stanadrd deviation of this random variable is the square root of the variance
rules for means ( if x is a random variable and a and b are constants) mua+x=a+mux, mubx=bmux, mua+bx=a+bmux, mux+y=mux+muy
rules for variances var (a+x)=var(x), var(bx)=bsqauredvar(x)
var (x+y)= var(x)+var(y)
var(x-y)= var(x)+var(y)
law of large numbers the difference between a sample proportion and a poporlation propoertion must gegt smaller as the sample size gets larger"
Created by: lilee256