Which condition is potentially violated?

Answer: Independence A pattern in residuals over time suggests serial correlation, violating the independence condition.

Which graph best checks "Normal residuals"?

Answer: Histogram or QQ plot of residuals Normality of residuals is assessed via a histogram or QQ-plot of the residuals.

Which letter represents constant residual variance?

Answer: E (Equal variance) "E" stands for Equal variance — residuals should have constant spread across all x values (homoscedasticity).

AP Statistics · Topic 9.1

Introducing Statistics: Do Those Points Align? Practice

Part of Inference for Quantitative Data: Slopes.(VAR-1.J)

Practice questions

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Sample questions

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Sample 1difficulty 2/5
$Residuals from a regression appear to be patterned over time (data collected sequentially).$
$Which condition is potentially violated?$
- A
  $Independence$
  check_circle
- B
  $Linearity$
- C
  $Equal variance$
- D
  $Random sampling$
Why
$A pattern in residuals over time suggests serial correlation, violating the independence condition.$
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Sample 2difficulty 2/5
$Conditions for slope inference are typically remembered with LINER.$
$Which graph best checks "Normal residuals"?$
- A
  $Histogram or QQ plot of residuals$
  check_circle
- B
  $Residuals vs time$
- C
  $Bar chart$
- D
  $Scatter of y vs x$
Why
$Normality of residuals is assessed via a histogram or QQ-plot of the residuals.$
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Sample 3difficulty 2/5
$Students perform inference on slope and check the LINER conditions.$
$Which letter represents constant residual variance?$
- A
  $L (Linear)$
- B
  $E (Equal variance)$
  check_circle
- C
  $N (Normal)$
- D
  $I (Independent)$
Why
$"E" stands for Equal variance — residuals should have constant spread across all x values (homoscedasticity).$
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Sample 4difficulty 3/5
$A residual plot shows a clear curved (parabolic) pattern.$
$Which condition is violated?$
- A
  $Equal variance$
- B
  $Random sampling$
- C
  $Linearity$
  check_circle
- D
  $Independence$
Why
$A curved pattern in the residuals indicates the underlying relationship is not linear; the linearity condition is violated.$
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Sample 5difficulty 3/5
$Slope inference is a special case of$
- A
  $Chi-square$
- B
  $Two-proportion z$
- C
  $F test for variance$
- D
  $t-procedure (one-sample t on slope)$
  check_circle
Why
$Slope test is a t-test using SE(b) and df = n - 2.$
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