A 42-year-old woman with obesity (BMI 34 kg/m²) presents for metabolic evaluation. Vital signs: BP 138/82 mmHg, HR 88 bpm, RR 14/min, temp 37°C. Fasting insulin is 18 mIU/L. Researchers perform simple linear regression modeling weekly exercise hours versus fasting insulin across 85 obese adults. The residual plot demonstrates a clear U-shaped pattern rather than random scatter around zero. HbA1c is normal at 5.2%. Which conclusion is most appropriate regarding model assumptions?
- A)The linearity assumption is likely violatedGABARITO
- B)The outcome must be categorical
- C)The sample size is too large
- D)There is complete absence of confounding
- E)The model has perfect calibration
Explicação
A residual plot with a systematic U shaped pattern suggests that the true relationship is not linear and that the linearity assumption has been violated. In a well specified linear model, residuals should be randomly scattered without obvious structure. A nonl... Ver explicação completa e trilha adaptativa →