A high school teacher in a low-income urban school in Worcester, Massachusetts, used cash incentives to encourage student learning in his AP statistics class. In 2019, 15 of the 61 students enrolled in his class scored a 5 (the highest possible score) on the AP exam. Worldwide, the proportion of students who scored a 5 in 2019 was 0.15. Is this evidence that the proportion of students who would score a 5 on the AP statistics exam when taught by the teacher in Worcester using cash incentives is higher than the worldwide proportion of 0.15?

• State hypotheses, find the p-value, and give conclusions in the context of the problem. Do we have any reservations about using the Z test for proportions for this data?
• Does this study provide evidence that cash incentives cause an increase in the proportion of 5s on the AP statistics exam? Explain answer.