Handedness: The preferential use of one hand for most fine manual tasks. Right handedness is the preferential use of the right hand while left handedness is the preferential use of the left hand for most fine manual tasks. Being able to use both hands equally well is known as being ambidextrous. Approximately 90% of the population is right-handed while about 10% is left-handed. A very small percentage of the population is ambidextrous.
One study claimed that right-handed people live longer than lefties, as reflected by a decline in the proportion of lefties in the population with age. This study has since been repeatedly refuted.