Many young men in North America and Europe (but not in Asia) tend to think they need more muscle to be attractive. One study presented 200 young American men with 100 images of men with various levels of muscle. Researchers measure level of muscle in kilograms of fat-free body mass per square meter of body surface area (kg/m). Typical young men have about 20 kg/m. Each subject chose two images, one that represented his own level of body muscle and one that he thought represented "what women prefer." The mean gap between self-image and "what women prefer" was 2.35 kg/m. Suppose that the "muscle gap" in the population of all young men has a Normal distribution with standard deviation 2.5 kg/m. If young men thought that their own level of muscle was about what women prefer, the mean "muscle gap" in the study would be 0. We suspect (before seeing the data) that (most) young men tend to think women prefer more muscle than they themselves have. What is the value of the test statistic z? Give your answer to two decimal places. Z=