The study reported in an article was motivated by publicity concerning the increased accident rate for individuals climbing ladders. A number of different gait patterns were used by subjects climbing a portable straight ladder according to specified instructions. The following data consist of climbing times for seven subjects who used lateral gait and six subjects who used a four-beat diagonal gait: Lateral gait 0.86 1.31 1.64 1.51 1.53 1.39 1.09 Diagonal gait: 1.27 1.82 1.66 0.85 1.45 1.24

a. Use the rank-sum test to decide whether the data suggest a difference in the mean climbing times for the two gaits.