The four main elements of the human body are oxygen, hydrogen, carbon, and nitrogen.
An effective speech should be organized around two or three main points.
Lets say that there are 5 people in a room and their ages are: 2,4,4,16,18
The range is the distribution of values: here it's from 2 to 18.
the mode is the correct answer! here it's 4.
the mean is the average: here it' s 22
the median is 4: the middle value.