Dispersion is contrasted with location or central tendency, and. Measures of dispersion are closely related to measures of central tendency. These are often called descriptive statistics because they can help you describe your data. These are the range, variance, absolute deviation and the standard deviation. Gholba measures of central tendency according to prof bowley measures of central tendency averages are statistical constants which enable us to comprehend in a single effort the significance of the. It tells the variation of the data from one another and gives a clear idea about the distribution of the data.
Lesson 5 measures of dispersion outline measures of dispersion. There are different measures of dispersion like the range, the quartile deviation, the mean deviation and the standard deviation. Notes, exercises, videos, tests and things to remember on measures of dispersion. Copies of these textbooks may be downloaded and used as textbooks or for reference. Please note that not all the institutions may get mapped due to. Notes of ecco measures of dispersion for class 11 chapter 6 download pdf. Ppt measures of dispersion powerpoint presentation. Measures of dispersion article about measures of dispersion. The observations may be close to the center or they may be spread away from the center.
Statistical dispersion means the extent to which a numerical data is likely. Notes of ecco measures of dispersion for class 11 download pdf. A measure of the spread of a distribution out from its central value. The above measures of mean deviation are absolute measures as all these contain the original units of the items. Measures of dispersion measures of variability that address the degree of clustering of the scores about the mean. On the other hand, the relative measures of dispersions are obtained as the ratio of the absolute measure of dispersion to the suitable average. In other words, if the measurements are in metres or seconds, so is the measure of dispersion. Visualizing dispersion to begin our discussion, let us suppose that in a penology class, three teach. Aug 17, 2019 measures of dispersion are used to describe the variability or spread in a sample or population.
The word dispersion has a technical meaning in statistics. Most measures of dispersion have the same units as the quantity being measured. In 4, 6, 9, 3, 7 the lowest value is 3, and the highest is 9. Two data sets can have the same mean but they can be entirely different. They are usually used in conjunction with measures of central tendency such as the mean and the median. Lesson initiator what is the purpose of finding an average. What are measures of central tendency and dispersion. The average measures the center of the data, and it is one aspect of observation. Are most scores relatively close to the mean, or are they scattered over a wider interval and thus farther from the mean. Age of a sample of 10 subjects from a population of 169subjects are. Chapter 5 measure of dispersion statistics mat studocu.
View notes lecture notes on measures of dispersion from math 2620 at valdosta state university. Measures of dispersion describe the spread of data around a central value mean, median or mode. To explain the meaning of dispersion, let us consider an example. Dispersion is the extent to which values in a distribution differ from the average of the distribution. Two kinds of statistics are frequently used to describe data. Ppt measures of dispersion powerpoint presentation free. Measure of central tendency give us good information about the scores in our distribution. Averages are also called measures of central tendency. Brief notes on the definitions, importance and properties of. Statistics measures of central tendency and dispersion class 2 session 2 oscarbarrera oscardavid.
Gholba measures of central tendency according to prof bowley measures of central tendency averages are statistical constants which enable us to comprehend in a single effort the significance of the whole. Measures of central tendency and cross tabulation lecture 8. Ncert textbook measures of dispersion commerce notes. Brief notes on the definitions, importance and properties. A measure of statistical dispersion is a nonnegative real number that is zero if all the data are the same and increases as the data become more diverse. Measures of dispersion are descriptive statistics that describe. The measures of central tendency are not adequate to describe data. As the name suggests, the measure of dispersion shows the scatterings of the data. Dispersion, pg 128 the extent of clustering or spread of the scores around the mean. Measures of dispersion definition measures of dispersion. Range, interquartile range, and standard deviation.
Another feature of the observation is how the observations are spread about the center. To make them free from units, we calculate their relative measured which are defined below. 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. Measures of central tendency are used because they represent centralized or middle values of the data. Characteristics of a good measure of dispersion an ideal measure of dispersion is expected to possess the. Notes on types of measures of dispersion,range, quartile. Measures of dispersion example question cfa level i. They tell us how much variability there is in the data.
Home up board question papers ncert solutions cbse papers cbse notes ncert books motivational. Statistics notes paper i unit iii notes prepared by prof mrs m. Cbse economics chapter 6 measures of dispersion class 11 notes economics in pdf are available for free download in mycbseguide mobile app. Measures of dispersion, also called measures of variability, address the degree of clustering of the scores about the mean. The extent of clustering or spread of the scores about the mean determines the amount of dispersion. Apr 05, 2020 ncert textbook measures of dispersion commerce notes edurev is made by best teachers of commerce. In simple terms, it shows how squeezed or scattered the variable is.
In lesson 2, you learned about frequency distributions, ratios, proportions, and rates. A free powerpoint ppt presentation displayed as a flash slide show on id. Dispersion is contrasted with location or central tendency, and together they are the most used properties of distributions. Brief notes on the definitions, importance and properties of dispersion. The below mentioned article provides a close view on the measures of dispersion in statistics. An outlier is a value that is much greater than or much less than most of the other values in a data set. Central tendencyvariability measures of central tendency. Measures of ccentral tendency and dispersion pdf free download important term and concepts. Definition central tendency measures do not reveal the variability present in the data. May 06, 2017 definition of measure of dispersion in statistics, dispersion also called variability, scatter, or spread is the extent to which a distribution is stretched or squeezed. Definition of measure of dispersion in statistics, dispersion also called variability, scatter, or spread is the extent to which a distribution is stretched or squeezed. Pdf on oct 1, 2011, s manikandan and others published measures of dispersion find, read. Measures of dispersion alevel mathematics statistics revision section of revision maths covering standard deviation, variance and quartiles. This document is highly rated by commerce students and has been viewed 942 times.
Dispersion is the state of getting dispersed or spread. Measures of dispersion are called averages of the second order because in precise study of dispersion, the deviations of the size of items from a measure of central tendency are calculated ignoring the signs and then these deviations are averaged. The range of a set of data is the largest measurement minus the smallest measurement. Copies of these textbooks may be downloaded and used as textbooks or. View notes measures of dispersion notes from math 120 at university of nevada, las vegas. Measures of dispersion tell you how widely spread out the values are most common are range, standard deviation, and variance range the range of a data set is the difference between the maximum and minimum values in the set example. While drawing conclusions and inferences to forecast and compare two or more than two data or series.
What are the measures of variation in data collection. Before we compute the value, lets learn some new definitions. For each of the following use the data set below for the example. They are measures of central tendency and dispersion. Examples interquartile range, standard deviation, variance. Md is based on all values and hence cannot be calculated for open. What is the importance of measures of central tendency in statistics.
It is a value which is typical or representative of a set of data. Measures of central tendency, dispersion, and assumptions lecture 7. Measures of dispersion class 11 notes edurev is made by best teachers of class 11. There are two main types of dispersion methods in statistics which are. Definition measures of dispersion are descriptive statistics that describe how similar a set of scores are to each other the more similar the scores are to each other, the lower the measure of dispersion will be the less similar the scores are to each other, the higher the measure of dispersion will be. Measures of dispersion, pg 128 measures of variability that addresses degree of clustering of the scores around the mean. In statistics, the measures of dispersion help to interpret the variability of data i. Thus to describe data, one needs to know the extent of variability. Mar 17, 2018 cbse economics chapter 6 measures of dispersion class 11 notes economics in pdf are available for free download in mycbseguide mobile app. I see outliers i see the shape of a dataset i find the range of values i find the median i find the quartiles i find the minimum and maximum values andreas artemiou chapter 1 lecture 4 measures of variability. Dispersion refers to the variation of the items around an average. Measures of dispersion mathematics alevel revision.
This document is highly rated by class 11 students and has been viewed 3870 times. Measures of dispersion notes chapter 12 section 3 page 1. May 23, 2018 apr 05, 2020 ncert textbook measures of dispersion commerce notes edurev is made by best teachers of commerce. Lesson 3 measures of central location and dispersion as epidemiologists, we use a variety of methods to summarize data. I give a test in a class and i take a sample of 6 students.
The more similar the scores are to each other, the lower the measure of. Dispersion the extent of clustering or spread of the scores about the mean. Statistics measures of central tendency and dispersion. Notes on measures of dispersion grade 11 economics. Literally, dispersion means deviation, difference or spread of certain values from their central value. Characteristics of a good measure of dispersion an ideal measure of dispersion is expected to possess the following properties 1.
Assumptions for measures of central tendency measures of dispersion. In analyzing, statistical data, it is often useful to have numbers describe the complete set of data. Measures of central tendency and dispersion pdf free download. Dispersion is the scattered ness of the data series around it average. Certain dispersive systems support sinusoidal waves only if the frequency is above or below a certain. Range, pg 129 simplest measure of dispersion that compares the highest score and the lowest score achieved for a given set of scores.
Central tendencyvariability statistics measures of central tendency and dispersion class 2 session 2 oscarbarrera oscardavid. Measures of dispersion class 11 notes economics mycbseguide. Method validation and comparisons with some most important tools of dispersion measures e. Notes, exercises, videos, tests and things to remember on types of measures of dispersion,range, quartile deviation, mean deviation. Measures of dispersion although the range is easy to compute it is a crude measure of variability.
The measure of dispersion shows the homogeneity or the heterogeneity of the distribution of the observations. Common examples of measures of statistical dispersion are the variance, standard deviation, and interquartile range. Outline measures boxplot exercises range variance standard deviation range i range is the distance between the minimum and the maximum value of the dataset i formula. Measures boxplot exercises iqr quartiles creating a boxplot usefulness of boxplots i boxplot is a graph that can be used to. The measures of central tendency are not adequate to describe. The best app for cbse students now provides measures of dispersion class 11 notes economics latest chapter wise notes for quick preparation of cbse exams and school based annual examinations. Ncert textbook measures of dispersion commerce notes edurev. An absolute measure of dispersion contains the same unit as the original data set.
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