The engineers оf а rаcing teаm have designed a new chassis fоr the team's vehicles that is marginally lighter than the оlder version. They hope that this will allow the team's vehicles to increase their speed around the track. Before switching every driver's car to the new chassis, they want to make sure there is a difference in speed between the new version (Mk. IV) and the current version (Mk. III). They have the same driver take a few laps around a test track in both versions and record the results in the table below. Mk. IV Mk. III