Chapter 6 review (Random Variables)

conditions/distributions

100

The population must be at least this much bigger than the sample size in order to be "close enough" on independence.

What is 10 times?

200

We are allowed to approximate this distribution if the expected number of successes and failures is large enough.

What is normal?

300

The minimum number for np and n(1-p) in order to use Mrs. Righter's most fave distribution.

What is 10?

400

BINS stands for this.

Binary

Independent

N is fixed

Success probability Same for all

500

The name of the distribution when the random variable is the number of trials and the number of successes is set at 1.

What is the geometric distribution?

Probability concepts

100

This is the sum of all of the probabilities in a sample space.

What is 1?

200

1-P(none)

What is P(at least 1)?

300

The probability for success and the sample size, respectively.

(looking for the variable names)

What are p and n?

400

The result when you multiply each value of x by its probability and add them all together.

What is the expected value of a discrete probability distribution?

500

The formula for P(X=x) when X~Bin(n,p)

What is nCr(n, x)*p^x*(1-p)^(n-x)?

Transformations

100

The mean of -3X, when X~N(mu_x, sigma_x)

What is -3*mu_x?

200

The standard deviation of X + 4 when X~N(mu_x, sigma_x)

What is sigma_x?

300

The mean of 2X + 3 when X~N(5,1).

What is 13?

400

The standard deviation of 1/4 X  when X~Unif(8,2).

What is 1/2?

500

The standard deviation of 0.3X - 1.7 when 

X~Poi(16.3, 0.3)

What is 0.09?

Combinations

100

For a random variable X with mean mu_x, this is the mean of X + X.

What is 2mu_x?

200

For random variables X and Y with means of mu_x and mu_y respectively, this is the mean of X - Y.

What is mu_x - mu_y?

300

For random variables X and Y, with means of 5 and 2 respectively, this is the mean of X - 3Y + 2.

What is 1?

400

For random variables X and Y with standard deviations sigma_x and sigma_y respectively, this is the standard deviation of X + Y.

What is the square root of the sum of the squared sigmas?

500

For random variables X and Y with standard deviations sigma_x and sigma_y respectively, this is the standard deviation of 2X - Y.

What is the square root of (4sigma_x² + sigma_y²)?

potpourri

100

This is what you call separating your population based on a common variable before sampling.

What is stratification?

200

This is when the outcome of one variable does not change the probability of another variable.

What is independent?

300

This is the number of standard deviations from the mean.

What is the Z-score?

400

This is a measure of spread that tells us the average distance from the mean.

What is standard deviation?

500

When you put all the values of a dataset in order and find the middle value(s).

What is the median?