AP Statistics 1.7: Comparing Summary Statistics

Studies have shown that foods rich in compounds known as flavonoids help lower blood pressure. Researchers conducted a study to investigate whether there was a greater reduction in blood pressure for people who consumed dark chocolate, which contains flavonoids, than people who consumed white chocolate, which does not contain flavonoids. Twenty-five healthy adults agreed to participate in the study and add 3.5 ounces of chocolate to their daily diets. Of the 25 participants, 13 were randomly assigned to the dark chocolate group and the rest were assigned to the white chocolate group. All participants had their blood pressure recorded, in millimeters of mercury (mmHg), before adding chocolate to their daily diets and again 30 days after adding chocolate to their daily diets.
The reduction in blood pressure (before minus after) for each of the participants in the two groups is shown in the dotplots below.

The researchers found the mean reduction in blood pressure for those who consumed dark chocolate is $\bar{x}_{\text {dark }}=6.08 \mathrm{mmHg}$ and the mean reduction in blood pressure for those who consumed white chocolate is $\bar{x}_{\text {white }}=0.42 \mathrm{mmHg}$.
Determine and compare the medians of the reduction in blood pressure for the two groups.

The researchers found the mean reduction in blood pressure for those who consumed dark chocolate is x_dark =6.08 mmHg and the mean reduction in blood pressure for those who consumed white chocolate is x_white =0.42 mmHg.

Determine and compare the medians of the reduction in blood pressure for the two groups.