In a clinical trial to check how effective a new blood pressure medication is, researchers recorded the blood pressure of 50 patients before and after they took the medication. Normally, a dependent sample t-test should be used because the before and after measurements are from the same patients. What could go wrong if the researchers use an independent sample t-test by mistake?
a. Using an independent sample t-test might igrlore how the before and after measurements are associated, leading to a higher chance of incorrectly finding a significant effect.
b. The t-value from the independent sample t-test would be smaller than it should be, possibly showing no effect of the medication when there actually is one.
c. The independent sample t-test would calculate group variances correctly but might miss real differences because it treats the groups as more spread out than they are.
d. The independent sample t-test might be too conservative, increasing the chance of type I error.