In 2015, a survey of first year university students in Brazil was conducted to determine if they knew how to activate the Mobile Emergency Attendance Service (MEAS). Of the 1,038 respondents (59.5% studying biological sciences, 11.6% physical sciences, and 28.6% humanities), 54.3% students of nonbiological subjects (n = 564) knew how to activate the MEAS as compared to 61.4% students of biological sciences (n = 637).

a. Estimate the difference between the proportions of students of biological sciences and nonbiological subjects who know how to activate the MEAS and interpret.

b. Find the standard error for this difference. Interpret it.

c. Define the two relevant population parameters for comparison in the context of this exercise.

d. Construct and interpret a 95% confidence interval for the difference in proportions, explaining how your interpretation reflects whether the interval contains 0.

e. State and check the assumptions for the confidence interval in part d to be valid.