ST 311 Exam 2

Numerical

Sample of means.

Null Hypothesis (H₀)

The statement of no change or no effect.

Alternative Hypothesis (Hₐ)

The claim you are testing

One-sided Test

Tests for increase or decrease only (>, <).

Two-sided Test

Tests for any difference (≠).

Type I Error:

Rejecting a true H₀ (false positive).

Type II Error:

Failing to reject a false H₀ (false negative).

Significance Level (α):

the cutoff probability for rejecting H₀ (often 0.05).

P-Value:

Probability of getting your sample result (or more extreme) if H₀ is true.

Decision Rule:

• If p < α → reject H₀.

• If p ≥ α → fail to reject H₀.

Confidence Level:

The percentage of confidence intervals that would contain the true parameter in repeated sampling.

Margin of Error (MOE):

How far your sample statistic could be from the true parameter.

Normal Condition for Proportions:

np≥10 and nq≥10.

Independent Samples:

Two separate groups.