AP Statistics Unit 9: Inference for Quantitative Data: Slopes

Unit 9 covers inference for regression slopes: confidence intervals and tests for the slope of a least-squares line, read largely from computer output. Locating the right number in the output is half the task.

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133 questions6 CED topics100% with a figure
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What 133 questions on it look like

100% of the questions come with a figure — a graph, diagram or data display. Reading the figure correctly is most of the work before any content knowledge applies.

Inference for the Slope of a Regression Model89
Carrying Out a Test for the Slope of a Regression Model17
Setting Up a Test for the Slope of a Regression Model15
Confidence Intervals for the Slope of a Regression Model5
Justifying a Claim About the Slope of a Regression Model Based on a Confidence Interval4
Introducing Statistics: Do Those Points Align?3

Questions per CED topic.

From the bank

Three real inference for quantitative data: slopes questions

Drawn from the practice pool, not from the mock papers.

Inference for the Slope of a Regression Model · Data Analysis · with figure

The data display records check values on a common scale. Which standard error belongs to Predictor B?

  1. A0.60
  2. B0.36
  3. C0.45
  4. D0.96correct
  5. E1.05
Why D is correct

The requested value is read from the Predictor B row under SE.

This is a strictblind AP Statistics figure item. The stem withholds the data needed to choose an answer, and the answer must be determined from the regression_output rendered from render_spec. The requested value or conclusion must be read from the regression output. The answer key is recomputed from the structured answer_rule.

Common mistakes. A common error is choosing a familiar-sounding statistics statement without checking the visual evidence in the figure.

Setting Up a Test for the Slope of a Regression Model · Selecting Statistical Methods · with figure

A study tests a nonzero linear relationship for slope for study sessions and quiz score gain. Which hypotheses use the correct parameter?

  1. AH0: beta = 0; Ha: beta != 0correct
  2. BH0: p-hat = 0; Ha: x-bar != 0
  3. CH0: beta != 0; Ha: beta = 0
  4. DH0: b = 0; Ha: b != 0
  5. EH0: sample statistic = 0; Ha: sample statistic differs
Why A is correct

The hypotheses should be H0: beta = 0 and Ha: beta != 0.

hypotheses for slope for study sessions and quiz score gain: in the "A study tests a nonzero linear relationship for slope for study sessions and quiz score gain. Which hypotheses use the correct parameter?" setting, especially slope for study sessions and quiz score gain; beta; beta = 0, state the hypotheses, compute the relevant test evidence, and conclude in context. The professional check is to keep the values 0, the hypothesis setup method, and the final answer choice aligned with Inference for Quantitative Data: Slopes.

Common mistakes. For the stem cue "A study tests a nonzero linear relationship for slope for study sessions and quiz score gain. Which hypotheses use the correct parameter?", a likely mistake is hypotheses should use population parameters, not sample statistics. Keep the calculation or conclusion tied to the original context.

Carrying Out a Test for the Slope of a Regression Model · Statistical Argumentation · with figure

Which statement describes a Type I error for false claim of a positive fertilizer slope?

  1. ACorrectly deciding when the true slope is 0.
  2. Bconcluding the fertilizer slope is positive when the true slope is 0.correct
  3. CUsing a sample size that is too large.
  4. DChanging alpha after seeing the data.
  5. EThe correlation or r-squared can be used as the regression slope because both describe a linear relationship.
Why B is correct

Type I error means rejecting a true null hypothesis: concluding the fertilizer slope is positive when the true slope is 0.

Type I error for false claim of a positive fertilizer slope: in the "Which statement describes a Type I error for false claim of a positive fertilizer slope?" setting, especially false claim of a positive fertilizer slope; Type I; the true slope is 0, choose the method that matches the wording of the stem and justify it with context. The professional check is to keep the values 0, 1, the type error method, and the final answer choice aligned with Inference for Quantitative Data: Slopes.

Common mistakes. For the stem cue "Which statement describes a Type I error for false claim of a positive fertilizer slope?", a likely mistake is this is a correct decision, not an error. Keep the calculation or conclusion tied to the original context.

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FAQ

Inference for Quantitative Data: Slopes questions

What does the slope’s p-value test?

Whether there is convincing evidence of a linear relationship — the null hypothesis is that the true slope is zero.

How do I read regression output?

The slope estimate and its standard error sit on the predictor’s row; the p-value on that row tests the slope, not the intercept.
Last reviewed 2026-08-28. Unit and topic names follow the College Board course framework. Question counts describe the PrepScore practice bank, not the exam.
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Inference for the Slope of a Regression Model93 questions
Same course
Unit 1: Exploring One-Variable Data460 questionsUnit 2: Exploring Two-Variable Data295 questionsUnit 3: Collecting Data190 questionsUnit 4: Probability, Random Variables, and Probability Distributions100 questionsUnit 5: Sampling Distributions70 questionsUnit 6: Inference for Categorical Data: Proportions107 questionsUnit 7: Inference for Quantitative Data: Means63 questions

Practise inference for quantitative data: slopes until the reasoning is automatic.

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