A food company is developing a new granola bar and its market analysts are currently working on preliminary studies of the packaging design. To help with a marketing strategy the company was first interested in whether the appeal of the packaging design for the new product (and hence the appeal of the product itself) was related to a person's gender. There were 100 male and 100 female volunteers available for purposes of evaluation. Both males and females rated the design on a scale of 1-10, 1 being "very unappealing" and 10 being "very appealing." The mean rating for males was 7.4 with a standard deviation of 1.5. The mean rating for females was 8.0, with a standard deviation 2.0. Let mu sub 1 and mu sub 2 represent the mean ratings we would observe for the populations of males and females, respectively. A 95% confidence interval for the difference mu sub 1- mu sub 2 is approximately?