APstats 9-12

What is a significance test?

A formal procedure used to observe data to decide between two competing claims (hypotheses).

What is the Null Hypothesis (H0)?

The claim that we weigh evidence against in a significance test.

What is the Alternative Hypothesis (Ha)?

The claim that we find evidence for in the significance test.

What is a one-sided test?

A test where the parameter can be either greater than or less than the null value (using < or >).

What is a two-sided test?

A test where the parameter can be different from the null (using < > or =).

What is the P-Value?

The probability of observing your data assuming the null hypothesis (H0) is true.

What is the Significance Level (α)?

A value used as a boundary to decide if the observed result is unlikely to happen by chance alone.

What is a Type 1 error?

The error that occurs when we reject the null hypothesis (H0) when it is actually true.

What is a Type 2 error?

The error that occurs when we fail to reject the null hypothesis (H0) when the alternative hypothesis (Ha) is true.

What are Standardized Test Results?

Measures how far a sample statistic is from what we would expect if the null hypothesis (H0) were true; it is calculated as (statistic - parameter)/SD.

What is Power in the context of significance testing?

The probability that the test will find convincing evidence for the alternative hypothesis (Ha) when a specific alternative value of the parameter is true.

What does paired data refer to?

Results from recording two values of the same quantitative variable for each individual or for each pair of individuals.

What is the Chi-Squared Test statistic (χ2)?

A measure of how far the observed counts are from the expected counts, calculated as χ2 = Σ(observed count - expected count)² / expected count.

What defines the Chi-squared Distribution?

A density curve that takes only nonnegative values and is skewed to the right.

What is the Population Regression Line?

The line represented by the equation y = a + bx, where y is the dependent variable.

What is the Sample Regression Line?

The estimated relationship represented by the equation ŷ = a + bx, where ŷ is the predicted value.