The study of dispersion is very important in statistical data. It is usually used in conjunction with a measure of central tendency, such as the mean or median, to provide an overall description of a set of data. Familiarity with the nature of variation in firm-level performance and growth and the accompanying turnover of firms within an industry is important for effectively evaluating a range of economic policies affecting labor and other markets, because both micro- and macroeconomic phenomena and policies affect and are affected by firm-level dispersion and reallocation. The three main ones are the range, the interquartile range and the standard deviation. (c) It is not a reliable measure of dispersion as it ignores almost (50%) of the data. 1. Thus, Range=Highest value of an item in a series - … Clearly, the extent of spread or dispersion of the data is different in section A from that of B. Mean deviation from mean. The measurement of the scatter of the given data about the average is said to be a measure of dispersion or scatter. In this article, we will consider measures of dispersion, which describe how the data is "dispersed" around a central value. The word variability is also used for the idea of dispersion. Dispersion is an important feature of observation and it is measured with the help of the measures of dispersion, scatter or variation. Important measures of dispersion are. Getting to know the range, interquartile range and standard deviation The three most important measures of dispersion are defined as […] This object of dispersion is of great importance and occupies a unique position in statistical methods. Dispersion measures the inequalities in the distribution of income and wealth. The measures of dispersion you use in psychology statistics show you the spread or variability of the variable you are measuring. 3. Measures of Dispersion A measure of spread, sometimes also called a measure of dispersion, is used to describe the variability in a sample or population. According to Spiegal, “The degree to which numerical data tend to spread about an average value is called variation or dispersion of the data.” Importance of Dispersion. Author's main message. Consider the following two sets of data which have the same mean, 25, and the same range, 10, but obvious di erences in the pattern of variability: 2 021 23 4 526 7 8 93 x x x x xx x x x x x x x 20 21 3 4 526 xx x x x x x x Da taSet1 DaSe2 Absolute measures of dispersion indicate the amount of variation in a set of values; in terms of units of observations. their average are called the dispersion. There are different measures of dispersion like the range, the quartile deviation, the mean deviation and the standard deviation. For example, when rainfall data is made available for different days in mm, any absolute measures of dispersion give the variation in rainfall in mm. Standard Deviation: The concept of SD as a successful measure of dispersion was introduced by the renowned statistician Karl Pearson in the year 1893 and it is still recognised as the most important absolute measure of dispersion. Measures of dispersion supplement the information given by the measures of central tendency: Measures of dispersion are also called averages of the ‘second order i,e., second time averaging the deviations from a measure of central tendency. range, mean deviation, and; standard deviation. Range is the simplest possible measure of dispersion and is defined as the difference between the values of the extreme items of a series. Measures of Dispersion Although the range is easy to compute it is a crude measure of variability. 1. In this lesson, you will read about the following measures of dispersion: Range. 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