Farren et al. (2004) compared the toughness of human fingernails along a transverse dimension (side to side) with the toughness along a longitudinal direction, with 13 measurements of each. the toughness of fingernails along a transverse direction averaged 3.3 kj/m2, with a standard deviation of 0.53, while the mean toughness along the longitudinal direction was 6.2kj/m2, with a standard deviation of 2.49. assume that the data are from two independent samples of 13 people