# ch 6 stats vocab

## 14 terms

### random variable

variable which has numerical values that describe the outcomes of some chance process

### probability distribution of a random variable

a random variable's possible valuesand their probabilities

### discrete random variable

a variable which has a fixed set of possible values with gaps between

### variance of a discrete random variable

Var (X) = 〖σ_x〗^2= ∑▒(x_i- μ_x )^2 p_i

### standard deviation

the square root of the variance.

### continuous random variable

a random variable which has all values in an interval of numbers

### independent random variables

knowing whether any event involving X alone tells us nothing about the occurrence of any event involving Y alone

### binomial setting

binary, independent, number, and success

### binomial random variable

the count X of success in a binomial setting

### binomial distribution

the probability distribution of a binomial random variable

### binomial coefficient

(n¦k)= n!/k!(n-k)! for k = 0, 1, 2, . . . n where

### geometric setting

binary, independent, trials, and success

### geometric random variable

the number of trials Y that it takes to get a success in a geometric

### geometric distribution

the probability distribution of a geometric random variable