# MIXED VOCAB FOR WINTER Flashcards

Minimum sample size for means?

If population is normalish, then there is no minimum sample size. If it is skewed or bimodal or any other non-normal distribution, then n>30.

What is a sampling distribution?

A pile of statistics taken from many many many samples

What are the the sample size requirements for inference for both means and proportions?

- [BOTH]You need a random sample. 2. [BOTH] Less than 10% of population 3. [DIFFER] PROPS: np>10 and nq>10, and MEANS n>30 unless from normal population, then no minimum.

What is formula for nCr ?

n! / r! (n-r) !

Describe independence and association with categorical examples.

Grade and pizzsa preference are independent, gender and gaming status are associated

How do you describe an association between two quantitative variables? (scatter plot)

DIRECTION (pos/neg) FORM (linear,curved) STRENGTH (strong, moderate, report “r” value)

Describe independence and association with quantitative examples.

Height and IQ are independent. Height and weight are associated.

function to find a percentile in normal model?

INVNORM

What is a p-value?

The likelihood you obtained your statistic or one more extreme due to just chance if the Null was actually true.

What is probability?

Long run relative frequency. (the long run percent)

Minimum sample size for proportions?

You need at lease 10 successes, np>10, and 10 failures, nq > 10

Interpret r^2 ?

The percent of variablility in Y explained by the model with X

What is error?

Distance from a statistic to the parameter. How far off your stat is from the truth.

What is a Z score?

the number of SD a data value is away from the mean

What graphs for CATEGORICAL data?

segmented bar, bar, pie, mosaic

What does SD of residuals tell us?

Typical residual. Average distance to the model. About how far off we expect model to be.