1. What is the calculation of observed – predicted?

✔ Residual
❌ Coefficient
❌ Notion
❌ Parameter

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2. Minimizing the sum of squared residuals is which method?

✔ Ordinary least squares
❌ Residual coefficients
❌ R squared
❌ Mean absolute error

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3. Waveform pattern violates which regression assumption?

✔ Linearity
❌ Independent observation
❌ Normality
❌ Homoscedasticity

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4. Scatterplot matrix shows _____ between variables.

✔ relationships
❌ distances
❌ variability
❌ discrepancies

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5. U-shaped residual pattern violates which assumption?

✔ Linearity
❌ Independent observation
❌ Homoscedasticity
❌ Normality

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6. Confidence band describes the _____ around predicted outcome.

✔ uncertainty
❌ inaccuracy
❌ certainty
❌ accuracy

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7. Which metric tells how much variation in X explains variation in Y?

✔ R squared
❌ P-value
❌ MSE
❌ MAE

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8. Which describe randomized controlled experiments?

✔ It is typically used when arguing for causation between variables.
✔ It is a study design that randomly assigns participants into groups.
❌ It cannot have a control group.
❌ Must control for every factor.

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9. Correlation r = 0.75 — which statements are true?

✔ Scatterplot slopes upward (r > 0).
✔ Regression line is steeper than r = 0.5.
❌ Slopes downward (wrong: that’s r < 0).
✔ Variables are positively correlated.

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10. X and Y correlation r = 1 (perfect positive). Points always on line:

Regression line is:
Y = 2 + 1·X → (X, X+2)

✔ (0, 2) → Yes
❌ (1, 1) → Should be 3
✔ (1, 3) → Correct
❌ (0, 0) → Should be 2

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🧾 Summary Table of All Answers

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