Multiple Comparisons (Bonferroni & Tukey HSD) with Confidence Intervals
Zaiontz’s Method for Multiple Comparisons

Exercise:
  Urine concentration of a certain substance (μg/day) in premature babies was measured to investigate the relation between urine substance concentration and gestational week.
  The gestational weeks were divided into 3 week-ranges, which are ‘<28weeks, 29 – 32 weeks, and 33 – 36 weeks’. The urine concentrations of the substance were measured at ‘1 week (within 7 days after delivery), 2 weeks (7 – 13 days), and 3 weeks (14 – 27 days)’. Results are shown below.
   Analyze whether there are statistically significant differences.