According to the published reports, practice under fatigued conditions distorts mechanisms which govern performance. An experiment was conducted using 15 college males who were trained to make a continuous horizontal right-to-left arm movement from a micro switch to a barrier, knocking over the barrier coincident with the arrival of a clock sweep hand to the6 o'clock position. The absolute value of the difference between the time, in milliseconds, that it took to knock over the barrier and the time for the sweep hand to reach the 6 o'clock position (500 msec) was recorded.

Each participant performed the task five times under prefatigue and postfatigue conditions, and the sums of the absolute differences for the five performances were recorded as follows. An increase in the mean absolute time differences when the task is performed under postfatigue conditions would support the claim that practice under fatigued conditions distorts mechanisms that govern performance. Assuming the populations to be normally distributed, test thisclaim.

Absolute Time Differences Prefatigue 158 Subject Postfatigue 91 92 59 215 226 223 91 92 177 134 05 98 33 89 148 58 142 4 6. LO 117 74 66 109 116 153 11 12 219 13 143 164 14 57 15 85 100 2.