Stats Ch. 6

Random variable

Takes numerical values that describe the outcomes of some chance process.

Dividing and multiplying a random variable by a constant changes the shape of the distribution.

False. It does not.

Adding or subtracting a constant from a variable…

Adds to measures of center and location. Does not change measures of spread or shape of distribution

Probability distribution of Y has same shape as probability distribution of X.

True

Mean of Sum of Random Variables

Variance of Sum of Random Variables

Mean of difference of variables is their difference BUT…

order of subtraction is important

binomial

“success” or “failure” in fixed number of trials

binomial settings conditions

Binary, Independent, Number, Success

p in binomial distribution

probability of success in any one trial

binomial probability formula

binompdf

use with specific number

binomcdf

find number greater or less than in a trial

mean of binomial random variable

standard deviation of binomial random variable

geometric setting

when we perform independent trials of the same chance process and record the number of trials it takes to get one success.

Probability of success in each geometric trial must be the same

True

geometric random variable

Y = number of trials needed to get first success

geometric distribution

probability distribution of geometric random variable

Formula of geometric probability

Formula for variance of geometric probability

Formula for mean of geometric probability