In a study comparing outcomes across 4 groups with continuous normally distributed data, the investigator performs 6 pairwise t-tests. The major methodological problem is:
- A Type I error (alpha) inflation due to multiple comparisons ✓
- B Type II error inflation
- C Loss of statistical power
- D Selection bias from improper group allocation
Correct answer: A. Type I error (alpha) inflation due to multiple comparisons
Explanation
When multiple pairwise comparisons are made, the probability of falsely rejecting at least one null hypothesis (Type I error) increases beyond the nominal alpha of 0.05. With 6 comparisons at alpha = 0.05, the familywise error rate rises substantially. This problem is addressed using ANOVA for overall comparison, and post-hoc tests such as Bonferroni correction, Tukey's HSD, or Scheffe's test to maintain the experiment-wide error rate. Multiple t-tests are not appropriate.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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