Basic Statistics

Section 2 Variation Fundamentals

Lesson S02-11

Text: Section 2 pages 72 – 96

Duration: 29 minutes

A statistic is a one number summary of a group of numbers. In other words, a statistic is one number which describes some characteristic of the data.

Some basic mathematical notation must be understood before attempting to estimate these three important aspects of a process.Many of the formulas used to compute statistics require the use of special notation, and it is this notation that is described next.

It is important to discriminate between a population and a sample. A population is a group that consists of everything being researched. For example, if the interest is on television viewing habits of American teenagers, then the population is all American teenagers.

A sample is a subgroup. Because it is usually impossible to acquire information on every unit in a population, it is more cost effective to select a subgroup. So, a sample is a subset of the population, and hopefully, the sample represents the population of interest.

Measures of Central Tendency include mean, median, and mode.

Measures of variation include range, standard deviation, and variance.

Basic Statistics

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Notation

Average & Central Tendancy

Measures of Variation