A Doctor Is Examining Differences Between Two Treatments

Multiple Choice

A doctor is examining differences between two treatments. He calculated a 95% confidence interval on the mean difference between the two groups. The interval ranged from -1.2 to 3.48. What does this suggest?

A) The mean difference is not significant at the .05 level
B) The mean difference has a small effect size
C) The mean difference is significant at the .05 level, but not at the .01 level.
D) The mean difference is not significant at the .05 level, but could still be significant at the .01 level.