In statistics, the quartile coefficient of dispersion is a descriptive statistic which measures dispersion and which is used to make comparisons within and between data sets. When the coefficient of quartile deviation is small, it indicates high uniformity or a small variation of the central 50% items or high uniformity towards the median performance. It is defined as Coefficient of Quartile Deviation = 31 31 3131 QQ 2 QQ QQQQ 2 = + + It is pure number free of any units of measurement. In my mind, they have a very specific use–for comparing the variability across datasets when measurements use different units. More examples Example 3: Calculate the range and coefficient of quartile deviation for the following sequence: \$1, 2, 4, 4, 6, 9, 9, 9, 10, 100\$. The quartile deviation calculated from the sample data does not help us to draw any conclusion (inference) about the quartile deviation in the population. Gastwirth (1982), "Statistical properties as a measure of tax assessment uniformity", Journal of Statistical Planning Inference, Vol. If one data set has a larger coefficient of quartile deviation than another data set, then that data set’s interquartile dispersion is greater. It is defined as: It is a pure number free of any units of measurement. 1-12. (a) Standard deviation (b) Range (c) Quartile deviation (d) Coefficient of variation MCQ No 4.22 The value is reported as a percentage of the median. Since it is based on quantile information, it is less sensitive to outliers than measures such as the Coefficient of variation.As such, it is one of several Robust measures of scale. They are less useful for understanding your own dataset. Applications: Reference: Bonett and Seier (2005), "Confidence interval for a coefficient of dispersion in nonnormal distributions", Biometrical Journal, Vol. Types of Measures of Dispersion. The coefficients of dispersion are calculated (along with the measure of dispersion) when two series are compared, that differ widely in their averages. If Q3=20 and Q1=10, the coefficient of quartile deviation is: (a) 3 (b) 1/3 (c) 2/3 (d) 1 MCQ No 4.21 Which measure of dispersion can be computed in case of open-end classes? There are four coefficients which are commonly referred, namely. When the coefficient of quartile deviation is small, it indicates high uniformity or fundamental rule about relative measures of dispersion here. This coefficient is a constant, rendering ready comparison of dispersion between data. A relative measure of dispersion based on the quartile deviation is called the coefficient of quartile deviation… Absolute Measure: Those measures of dispersion whose units are same as the units of the given series is known as the absolute measure of dispersion.These types of dispersions can be used only in the comparing the variability of the series or distribution having the same units. 144-148. The coefficient of dispersion (COD) is the average difference a group of numbers has from the median. Coefficient of Quartile Deviation. Co-efficient of Quartile Deviation; Co-efficient of Mean Deviation; Co-efficient of Dispersion. Types of Measures of dispersion,Range, Quartile Deviation, Mean Deviation. 48, pp. A relative measure of dispersion based on the quartile deviation is called the coefficient of quartile deviation. I have not used the coefficient of dispersion or quartile coefficient of dispersion much. It can be used for comparing the dispersion in two or more than two sets of data. A relative measure of dispersion based on the quartile deviation is called the coefficient of quartile deviation. 6, pp.