Fig. 4
This figure plots the time to complete the 10 km time trial after consuming khat or placebo for all 21 volunteers. Only one person took longer to complete the 10 km cycle when using khat while most volunteers finished about 2–3 min faster when using khat. To find out if there is a significant change in the time required to complete the 10 km cycle between using the placebo and khat, the differences in time taken were calculated