⚙️ 15 · Logistic Regression
Research Question:
Does weekly study hours predict the probability of passing (Y=1) vs failing (Y=0) an examination? n=20 students.
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1
MLE estimates (obtained via software):
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Predicted probabilities at key values:
| Study Hours | 6 | 7 | 8 | 9 | 10 |
| P(pass) | .115 | .283 | .550 | .798 | .922 |
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Odds Ratio — how much the odds multiply per extra hour:
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4
Model significance — Omnibus test:
✅ Study hours significantly predicts pass/fail, OR=3.06 — each additional study hour triples the odds of passing.
APA-7
Logistic regression was performed to examine whether study hours predicted exam outcome. The overall model was significant, χ²(1) = 14.5, p < .001, Nagelkerke R² = .72, correctly classifying 85% of cases. Study hours was a significant predictor, b = 1.12, SE = 0.48, Wald χ²(1) = 5.44, p = .020, OR = 3.06, 95% CI [1.19, 7.87].