At Westville High School there are 315 seniors and 389 juniors 65%. of the seniors have parking passes and 42% of the juniors have parking passes. The statistics teacher selects a SRS of 30 seniors and a separate SRS of 30 juniors. Let be the difference in the sample proportions of seniors and juniors that have parking passes. a. What is the shape of the sampling distribution of Why? b. Find the mean of the sampling distribution. c. Calculate and interpret the standard deviation of the sampling distribution. d. What is the probability that the difference in sample proportions (senior - junior) of students with parking passes is greater than ?