Class 11 Economics - CBSE
Measures of Dispersion
The chapter 'Measures of Dispersion' in Class 11 Economics introduces students to statistical tools used to measure the variability, scatter, or spread of data around a central value. While measures of central tendency give a single summary value, they do not reveal how diverse the data points are. This chapter covers both absolute measures (like Range, Quartile Deviation, Mean Deviation, and Standard Deviation) and relative measures (like coefficients of these measures). Dispersion is crucial for board exams because it forms the backbone of advanced statistical analysis in economics, frequently appearing as numerical problem-solving questions in the CBSE exam.
Start Learning FreeKey Concepts
Dispersion
Dispersion refers to the extent to which values in a statistical distribution are scattered or spread out around an average value.
Range
Range is the simplest measure of dispersion, calculated as the difference between the highest and lowest values in a given data set.
Mean Deviation
Mean Deviation is the arithmetic mean of the absolute differences of the observations from a central value, usually the mean or median.
Standard Deviation
Standard Deviation is the most widely used and mathematically rigorous measure of dispersion, representing the square root of the arithmetic mean of squared deviations from the mean.
Coefficient of Variation
The Coefficient of Variation is a relative measure of dispersion used to compare the variability of two or more data series, expressed as a percentage.
Important Formulas
Board Exam Info
In the CBSE Class 11 Economics (Statistics for Economics) examination, this chapter typically carries around 6 to 8 marks. Questions usually include direct numerical problems on calculating Standard Deviation or Mean Deviation, theoretical differences between absolute and relative measures, and application-based questions comparing variability of two datasets.
Frequently Asked Questions
Why do we need measures of dispersion if we already have measures of central tendency?
Measures of central tendency only give the average of a dataset, but they don't show how scattered the data is. Two datasets can have the exact same mean but completely different levels of risk or consistency, which dispersion helps us identify.
What is the difference between absolute and relative measures of dispersion?
Absolute measures are expressed in the same units as the original data (like rupees, kilograms) and cannot be used to compare two series with different units. Relative measures are pure ratios or percentages free of units, making them ideal for comparisons.
Why is Standard Deviation considered the best measure of dispersion?
Standard Deviation is mathematically stable, takes into account all observations in the data set, and is amenable to further algebraic treatment, making it the most reliable and scientifically accepted measure.
Learn Measures of Dispersion with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards