65 chemical engineering students are from urban/suburban backgrounds.
(Success is defined as a C or better in the course.)
52 of the 65 students succeeded.
Another 55 students were from rural backgrounds; 30 of these students succeeded.
A Is there good evidence that the proportion of students who succeed is different for urban/suburban vs. rural backgrounds?
B) Estimate the difference between the success rates for all urban/suburban and rural students who plan to study chemical engineering. Use 90% confidence.