People end up tossing 12% of what they buy at the grocery store. Assume this is the true population proportion and that you plan to take a sample survey of 540 grocery shoppers to further investigate their behavior. a. Calculate the mean and the standard error for the sample proportion p. b. Describe the sampling distribution of p in part a. Draw a graph of this probability distribution with its mean and standard deviation. c. What is the probability that your survey will provide a sample proportion more than 15%? d. What is the probability that your survey will provide a sample proportion within ± 0.03 of the population proportion?