Which hand do people prefer to use?

Answer 1

About 8 to 15% of people are lefthanded

Right Handedness is more common.

It is not a preference but genetic, people don't decide which hand is dominant.

There are exeptions;

* Mixed-handedness, also known as cross-dominance, is being able to do different tasks better with different hands. For example, mixed-handed persons might write better with their right hand but throw a ball more efficiently with their left hand. This could also refer to pianists, because different sections of pieces are usually composed to fit the abilities of the different hands, considering that the right hand is usually for melodies and the left-hand, harmonies. However, many writers refer to handedness as the hand that a person uses to write, so Mixed-handedness is often neglected. * Ambidexterity is exceptionally rare, although it can be learned. A true ambidextrous person is able to do any task equally well with either hand. Those who learn it still tend to sway towards their originally dominant hand.