The study reported in “Gait Patterns During Free Choice Ladder Ascents” (Human Movement...

The study reported in “Gait Patterns During Free Choice Ladder Ascents” (Human Movement Science [1983]: 187–195) 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 a lateral gait and six subjects who used a four-beat diagonal gait:

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

b. Interpret the 95% confidence interval for the difference between the mean climbing times given in the following Minitab output: