A dean of men wishes to estimate the average cost of the freshman year at a particular college correct to within $260, with a probability of 0.95. If a random sample of freshmen is to be selected and each asked to keep financial data, how many must be included in the sample? Assume that the dean knows only that the range of expenditures will vary from approximately $14,700 to $26,620. (Round your answer up to the nearest whole number.)