This lesson explains the meaning of variable, element, data set, and observation. These are some important basic terms to understand in statistics.

Imagine using cluster samples to estimate the number of gifted students in each state. You select 5 states and have ended with the following example.

Note that the table below does not contain any real statistical data.

States in the USA |
Number of gifted students |

Massachusetts | 500 |

new York |
600 |

Florida |
400 |

California |
600 |

Montana |
200 |

**record**

The information given in the table above is one data set. It’s just a collection of data usually organized with a table.

**element**

Each of the conditions listed in the table is an element or a member of the sample. For example, New York is a member or element of the sample.

An element can be an object, a state, a person, and so on.

**monitoring**

The assigned value **only one** Element is called an observation. For example, 600 is an observation. An observation is also known as a measurement.

**variable**

Everything it can hold **different** Values is called a variable. So the number of gifted students is a variable because it has different values.

Other examples of variables could include the number of students who graduated from college, senior citizen income, types of health insurance plans people are enrolled in.

Note that the variable types of health insurance do not give you numbers. More on this type of variable in the next lesson.

You can use any letter of the alphabet to represent a variable. The ones we prefer are x, y, or z.