The formula for a trapezoid relates the area a, the two bases, a and b, and the height, h. solve for a
a=(a+b)/2×h

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. what is the probability that your survey will provide a sample proportion more than 15%? c. d. population proportion? what is the probability that your survey will provide a sample proportion within + 0.03 of the