Unit 10 measures of dispersion and the normal distribution measures of dispersion why dispersion. Notes of ecco measures of dispersion for class 11 download pdf. The dispersion coefficient is also used when two series with different measurement unit are compared. Range and quartile deviation measure the dispersion by calculating the spr ead within which the values lie. Generally, when light passes from one medium to another, it bends at the surface separating the two. Measures of dispersion describe the spread of data around a central value mean, median or mode. Choose your answers to the questions and click next to see the next set of questions. The scatterness or variation of observations from their average are called the dispersion. Dispersion notes general xgnp graphene nanoplatelets are very thin, 5 10 nanometers in thickness flat particles with quite large diameters. It is also the facilitating technique to many other statistical techniques like correlation, regression, structural equation modeling, etc. Dispersion is known as the splitting up of white light into its 7 constituent colours.
Finding the range two reality cooking shows select 12 contestants each. They are usually used in conjunction with measures of central tendency such as the mean and the median. View notes measures of dispersion notes from math 120 at university of nevada, las vegas. In statistics, there are many techniques that are applied to measure dispersion. Such a number is called a measure of central tendency. In the instance where all scores are exactly at the mean, there is no dispersion at all. In addition to knowing central tendency, it is an absolute must that we know how the data is dispersed. It affords an estimate of the phenomena to which the given original data relate. Dispersion also helps a researcher in comparing two or more series. Jun 11, 2009 the second type is the relative measure of dispersion, which measures the ratio unit. Dispersion is the state of getting dispersed or spread. Measures based upon spread of values range range r is the dif ference between the largest l and the smallest value s. It is dispersion between the modes, caused by difference in propagation time for.
Standard deviationis the square root of the variance in calculating the variance of data points, we square the difference between each point and the mean. Measures of dispersion range notes the range is the simplest and easiest to calculate of the measures of dispersion. Measures of dispersion notes chapter 12 section 3 page 1. Measures of central tendency, dispersion, and assumptions lecture 7. Practics question for ch 10 measures of dispersion exercise 1. Measures of dispersion there are three main measures of dispersion. The dispersion which is independent of modes, related to the line width of the source and caused by variations in the refractive index as a function of wave length is called intra model dispersion. These are the range, variance, absolute deviation and the standard deviation. Measures of dispersion class 11 notes economics mycbseguide. Varianceis the average squared difference of scores from the mean score of a distribution.
Measures of dispersion article about measures of dispersion. It is a better measure of dispersion than the range because it involves more items than the range. Pdf on oct 1, 2011, s manikandan and others published measures of dispersion find, read and cite all the research you need on researchgate. In case of an individual series, standard deviation is calculated by using the following formula. Among all the measures of dispersion, the standard deviation is considered superior because it possesses all the requisites at a good measure of dispersion. Those measures of dispersion whose units are same as the units of the given series is known as the absolute measure of dispersion. The minimum number of completions for quarterback a is 19, the maximum is 37. Statistical dispersion means the extent to which a numerical data is likely to vary about an average value. Users can download cbse guide quick revision notes from mycbseguide mobile app and my cbse guide website. If we divide a cumulative frequency curve into quarters, the value at the lower quarter is referred to as the lower quartile, the value at the middle gives the median and the value at. Range r xh xl largest value smallest value in data set measures of dispersion standard deviation sample standard deviation. Useful notes on dispersion of light explained with diagram. Md is based on all values and hence cannot be calculated for open.
Measures of dispersion are also called averages of the second order i,e. Another feature of the observation is how the observations are spread about the center. 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. Aug 09, 20 measure of dispersion part i range, quartile deviation, interquartile deviation, mean deviation 1. The word dispersion has a technical meaning in statistics. Range is defined as the difference between the upper boundary of last class interval and the. Calculate the difference between each value and the mean. The below mentioned article provides a close view on the measures of dispersion in statistics. Variance and standard deviation by far the most commonly used measures of dispersion in the social sciences are varianceand standard deviation.
The range of a set of data is the largest measurement minus the smallest measurement. Measures of dispersion measure how spread out a set of data is. Measures of dipersion class 11 notes economics chapter 6 in pdf format for free download. It includes all the topics given in ncert class 11 economics text book. The second important characteristic of a distribution is given by dispersion. As a result, a sample always has the tendency of underestimating the standard. These types of dispersions can be used only in the comparing the variability of the series or distribution having the same units. Measures of dispersion although the range is easy to compute it is a crude measure of variability. The following figure shows a number of distributions having identical measure of central tendency and yet. While measures of central tendency are used to estimate normal values of a dataset, measures of dispersion are important for describing the spread of the data, or its variation around a central value.
Here, the measure of central tendency is not giving a clear. Mathematical reasoning content page d2l course log in. Aug 17, 2019 measures of dispersion are used to describe the variability or spread in a sample or population. Objectives of dispersion a to determine the reliability of an average. Introduction in addition to finding measures of central tendency for a set of scores, we also calculate measures of dispersion to aid us in describing the data. Types of measures of dispersion,range, quartile deviation. 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, pg 128 measures of variability that addresses degree of clustering of the scores around the mean. The difference between the upper and lower quartile is known as the interquartile range.
Dispersion away from the centre, unlike central tendency which connotes. Measures of dispersion class 11 notes edurev is made by best teachers of class 11. Notes, exercises, videos, tests and things to remember on measures of dispersion. An ideal measure of dispersion is expected to possess the following properties 1. Dispersion refers to the variation of the items around an average. Range r xh xl largest value smallest value in data set measures of dispersionstandard deviation sample standard deviation. It is the difference between the largest and smallest observation. Assumptions for measures of central tendency measures of dispersion descriptive statistics. Measures of dispersion are closely related to measures of central tendency.
Standard deviation ungrouped technique kurtosis kurtosis provides information regrading the shape of the population distribution the peakedness or. About measures of dispersion measures of dispersion. In this chapter, we will cover four measures of dispersion. Cbse guide notes are the comprehensive notes which covers the latest syllabus of cbse and ncert. Notes on measures of dispersion grade 11 economics. Measures of dispersion definition measures of dispersion. Dispersion is the scattered ness of the data series around it average. Pdf on oct 1, 2011, s manikandan published measures of dispersion find, read and cite all the research you need on researchgate. Two distributions may be identical in respect of its first important characteristic i.
The average measures the center of the data, and it is one aspect of observation. The reason why sd is a very useful measure of dispersion is that, if the observations are from a normal distribution, then 68% of observations lie between mean 1 sd 95% of observations lie between mean 2 sd and 99. It is the difference between the lowest value and the highest value in the distribution. Range is the simple measure of dispersion, which is defined as the difference between the largest value and the smallest value. The dispersion which is caused by the delay between different modes is called inter model dispersion.
Unit 10 measures of dispersion and the normal distribution. Measures of dispersion mathematics alevel revision. The arithmetic mean of the deviations of the values of the individual items from the measure of a particular central tendency used. Since intra model dispersion depends on line width which is related to color. The standard deviation steps for calculating standard deviation 1. 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 dispersion example question cfa level i. Shakehand with life promoting quality culture in every sphere of human life page 2. Dispersion is the extent to which values in a distribution differ from the average of the distribution. The other advantage of sd is that along with mean it can be used to detect skewness. The standard deviation, s, is the square root of the variance. Two distinct samples may have the same mean or median, but completely different levels of variability, or vice versa. The bending of light when light travels from one medium to another is called refraction of light.
Measures of central tendency and cross tabulation introduction measures of central tendency mct allow us to summarize a whole group of numbers using a single number. Therefore it is also called chromatic dispersion color. Measure of dispersion part i range, quartile deviation, interquartile deviation, mean deviation 1. Sampling, measurement, distributions, and descriptive statistics the mean the mean is defined as the arithmetic average of a set of numerical scores, that is, the sum of all.
Suppose you have four datasets of the same size and the mean is also same, say, m. This document is highly rated by class 11 students and has been viewed 3882 times. The measures of dispersion you have just seen differ in ways that will help determine which one is most useful in a particular situation. Dispersion, pg 128 the extent of clustering or spread of the scores around the mean. Dispersion and measures of dispersion in statistics measures of dispersion in statistics, the measures of dispersion help to interpret the variability of data i. Range is defined as the difference between the upper boundary of last class interval and the lower boundary of first class boundary of the distribution. The measure of dispersion shows the homogeneity or the heterogeneity of the distribution of the observations. The dispersion can be divided into two general categories. Thus the dispersion is also known as the average of the second degree. In measuring dispersion, it is imperative to know the amount of variation absolute measure. You can skip questions if you would like and come back to. This document is highly rated by class 11 students and has been viewed 11404 times.
Mean deviation and standard deviation calculate the extent to which the values differ from the average. After reading this article you will learn about the measures of dispersion which is designed to state numerically the extent to which individual observation vary in the average. This will increase the accuracy of statistical analysis and interpretation and we can be in a position to draw. The first is the absolute measure, which measures the dispersion in the same statistical.
Measures of central tendency and cross tabulation lecture 8. Example calculate the range for the data for quarterback a and quarterback b in the example above. Half the interquartile range is known as semiinterquartile range or quartile deviation. Chapter 4 measures of dispersion range quartiles variance standard deviation coefficient of variation. Measures of dispersion range notes measures of dispersion.
Light can travel through various mediums like air, glass, water and oil. Dispersion is contrasted with location or central tendency, and. Measure of dispersion part i range, quartile deviation. There are different measures of dispersion like the range, the quartile deviation, the mean deviation and the standard deviation.
Next, we want to calculate the distance of each data value from given a data value x i, a simple difference such as x i. Definition central tendency measures do not reveal the variability present in the data. Certain dispersive systems support sinusoidal waves only if the frequency is above or below a certain cuto. The measure of dispersion depending upon the lower and upper quartiles is known as the quartile deviation. Of all the measures of dispersion, the range is the easiest to determine.
Because of the flat shape of these particles, they. Like other nanoparticles, the small size gives rise to certain handling issues. The coefficients of dispersion are calculated along with the measure of dispersion when two series are compared which differ widely in their averages. The observations may be close to the center or they may be spread away from the center. They tell us how much variability there is in the data. In all the cases the sum of the observations will be the same. Range, pg 129 simplest measure of dispersion that compares the highest score and the lowest score achieved for a given set of scores. These types of dispersions can be used only in the comparing the variability of the. Dispersion pl 2pl 3pl 4pl 2w0 w k slope wk phase velocity figure 3 there are various things to note about this. In 4, 6, 9, 3, 7 the lowest value is 3, and the highest is 9.
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