$2.$ A graduate student in biomechanics was interested in stride length of cross$-$country skiers. Stride length is an important factor in the development of speed for racing. Data were collected on $20$ athletes from the cross$-$country ski team $($the experimental group$).$ The data were compared with those of a second group of $17$ students $($the control group$)$ who were not varsity athletes but did participate in recreational skiing. The researcher assumed that no significant differences would be found. Does a significant difference in stride length exist between the athletes and the nonathletes? What is the level of confidence? What is $\backslash$omega $2,$ and what is the effect size? $($Adapted from Duoos, $1984$; data fabricated.$)$