Concert marketing: the college’s performing arts center wanted to investigate why ticket sales for the upcoming season significantly decreased from last year’s sales. the marketing staff collected data from a survey of community residents. out of the 110 people surveyed, only 7 received the concert brochure in the mail. which of the following is a reason that the marketing staff should not calculate a confidence interval for the proportion of all community residents who received the concert brochure by mail? check all that apply. a. the sample needs to be random, but we don’t know if it is. b. the actual count of community residents who received the concert brochure by mail is too small. c. the actual count of students who community residents who didn’t receive the concert brochure by mail is too small. d. n(p? hat) is not greater than 10.e. n(1 minus p? hat) is not greater than 10.