The average middle-distance runner at a local high school runs the mile in 4.5 minutes, with a standard deviation of 0.3 minute. The percentage of a runners that will run the mile in less than 4 minutes is %.

Question

The average middle-distance runner at a local high school runs the mile in 4.5 minutes, with a standard deviation of 0.3 minute. The percentage of a runners that will run the mile in less than 4 minutes is  %.

anonymous · Answer

$$mean \pm s.d$$ we have to see where our runner lies in terms of the mean and the deviation,
the runners that run less than 4 min are within two s.d from the mean
$$4,5\pm2*0,3$$
between 4,5-0,6=3,9 and 4,5+0,6=5,1
and these is approaximately 95%

anonymous · Answer

tthanks