AP Statistics: Core Concepts

What is a Simple Random Sample (SRS)?

A sample of size n where every group of n individuals in the population has an equal chance of being selected.

What is the range of possible values for the correlation coefficient (r)?

The correlation coefficient r must be between -1 and 1, inclusive.

Define a P-value in the context of a significance test.

The probability of observing a test statistic as extreme or more extreme than the one calculated, assuming the null hypothesis is true.

If a distribution is skewed to the left, how do the mean and median typically compare?

The mean is typically less than the median because it is pulled toward the long tail of low values.

What is a Type I error?

Rejecting the null hypothesis when it is actually true (a false positive).

According to the Empirical Rule (68-95-99.7), what percentage of data falls within two standard deviations of the mean in a normal distribution?

Approximately 95% of the data.

What is the difference between a parameter and a statistic?

A parameter describes a population, while a statistic describes a sample.

How do you interpret the standard deviation of a dataset in context?

The standard deviation represents the typical or average distance that data points fall from the mean of the distribution.

What does it mean to be '95% confident' in a confidence interval?

If we take many samples and build intervals the same way, about 95% of those intervals will capture the true population parameter.

What are the four conditions required for a Binomial distribution (BINS)?

Binary (success/failure), Independent trials, fixed Number of trials, and Same probability of success for each trial.