AP Statistics · Week 9 Practice Workbook

Unit 9 · Inference for
Quantitative Data: Slopes

Conditions for regression (LINER) · confidence intervals & hypothesis tests for the slope · interpreting the t-statistic

Questions

100

Format

MCQ

Suggested Time

150 min

Topics

9.1–9.3

Name

Date

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Formula & Reference Sheet

LINER Conditions

Linear · Independent · Normal · Equal variance · Random

Checked mainly with a residual plot & residual histogram.

Hypotheses

H₀: β = 0 vs Hᵣ: β ≠ 0 (or >, <)

β = true population slope; b = sample slope estimate.

Degrees of Freedom

df = n − 2

Two parameters (intercept & slope) are estimated first.

Standard Error of Slope

SE_b = s / √Σ(x − x̄)²

s = residual standard deviation.

Confidence Interval

b ± t* · SE_b

t* comes from the t-distribution at df = n−2.

Test Statistic

t = (b − β₀) / SE_b

Measures how many SE_b's b is from β₀ (usually 0).

Unit 9 · Inference forQuantitative Data: Slopes