Sentences to Know for AP Stat Test

What are the four principles of experimental design

Random assignment, control, compare, replication

What is the Law of Large Numbers?

The proportion of times that a particular outcome occurs in many repetitions will approach a single number

What is the Central Limit Theorem

when a simple random sample is drawn from any population with mean µ and standard deviation ø, the central limit theorem says that when n is large the sampling distribution of the sample mean X-bar is approximately normal

How to you interpret the probability of an event

if the event occurred many, many times the proportion of “the outcome you are looking for” will be about __

How to describe a graph?

Center, shape, spread, outliers

how to interpret slope of LSRL

for each increase by 1 unit in the x variable, the predicted value of y will increase/decrease by the slope amount on average

how to interpret the y intercept of an LSRL

the predicted response of y when x = 0

Define p-value

if the null hypothesis were true then there is a p value probability of observing a test statistic at least as extreme as the one observed

define statistically significant

a result that is statistically significant is a result that is not due to random chance. The probability that the result occurred is very low given the null hypothesis is true

interpret a confidence interval

If many samples are take then about C% of the intervals will capture the true parameter being estimated

interpret the confidence level

the confidence level gives us overall success rate of the method for calculating the confidence interval. In C% of al possible samples the method would yield an interval that captures the true parameter.

sentence for coefficient of determination (r²)

__% of the variability in y is explained by the linear relationship of y on x (about r²% of the variability in y is accounted for by the LSRL)

How to choose an SRS

Label individuals on equal sized pieces of paper. Put the papers in a hat, mix well, and select n pieces, mixing well after each selection.

What makes a binomial distribution? (BINS)

Binary (pass/fail), Independent, Number (of trials fixed), Success (probability of success fixed)

what makes a geometric distribution (BITS)

Binary (pass/fail), Independent, Trials (trials until success), Success (probability of success is fixed)

Sentence for mean (expected value) of a random variable

if many, many (context) are chosen at random, the average (context) es about E(x) units

Standard deviation of a random variable

A randomly selected (context) will typically vary from the mean by about S(x) units

Unbiased estimator

a statistic used to estimate a parameter is unbiased estimator if the mean of the sampling distribution is equal to the true value of the parameter being estimated

Percentile sentences

P% of sample population are less/smaller than the individual

or

the individual is more/greater than P% of sample population

interpret Z score

data item is Z score standard deviations above/below the mean

Coefficient of Correlation sentence, r

there is a (strength), (direction) linear relationship between x and y