A clinical study investigates a possible impact of an antihypertensive medication on the systolic blood pressure. As a result, we observed the systolic blood pressure lowered by more than 7 mmHg in 43 out of 56 patients who received that medication. Such systolic blood pressure lowering (i.e., by more than 7 mmHg) was also observed in 21 out of 58 patients who received a placebo.

(a) (2 marks) Construct an appropriate contingency table for the observed data.

(b) (2 marks) Determine the probability for a patient who receives the considered medica- tion to lower their systolic blood pressure by more than 7 mmHg. Determine the same probability for a patient who receives placebo.

(c) (4 marks) Can we state that the considered medication does lead to a lowering of the systolic blood pressure? Justify your answer for full credit.