AP Stats Ch. 20

Null hypothesis…

The claim being assessed in a hypothesis test.

A statement of “no change from the traditional value,” “no effect,” “no difference,” or no “relationship.”

Must specify a value for some POPULATION PARAMETER (P) that can form the basis for assuming a sampling distribution for a test statistic.

H₀

Alternative hypothesis…

Proposes what we should conclude if we find the null hypothesis to be unlikely.

H_A

Two-sided alternative…

(H_A: p ≠ p₀)

When we are interested in deviations in EITHER direction away from the hypothesized parameter value (p-value).

One-sided alternative…

(e.g., H_A: p > p₀ or H_A:p < p₀)

When are interested in deviations in ONLY ONE direction from the hypothesized parameter value (p-value)

P-value…

The probability of observing a blue for a test statistic at least as far from the hypothesized value as the statistic value actually observed if the null hypothesis is true.

A small P-value indicates that the observation is improbable or that the probability calculation was based on incorrect assumptions.

The assumed truth of the null hypothesis is the assumption under suspicion.

One-proportion z-test…

A test of the null hypothesis that the proportion of a single sample equals a specified value (H₀: p = p₀) by referring the statistic

z = statistic - parameter / standard error of the statistic

= p̂ - p / √p (1-p) / n

to a Standard Normal model.