Class 11 Maths - CBSE
Statistics
The Statistics chapter in Class 11 CBSE Mathematics moves beyond basic mean, median, and mode from earlier grades to introduce measures of dispersion. You will learn how to measure how spread out data is from a central value. The main topics include Range, Mean Deviation (for both ungrouped and grouped data), Variance, and Standard Deviation. This chapter is vital for board exams and lays the foundational statistical thinking required for higher education, competitive exams, and data analysis.
Start Learning FreeKey Concepts
Measures of Dispersion
Statistical measures that help us understand how scattered or spread out the data values are around the central tendency.
Mean Deviation
The average of the absolute differences between each data point and the mean or median of the dataset.
Variance
The average of the squared differences from the mean, providing a clearer picture of data variability.
Standard Deviation
The positive square root of the variance, expressed in the same units as the original data.
Coefficient of Variation
A dimensionless measure used to compare the variability of two or more different data series.
Important Formulas
Board Exam Info
In the CBSE Class 11 Mathematics final exam, Statistics typically carries around 6 to 8 marks. Common question types include calculating Mean Deviation for discrete and continuous frequency distributions, and finding Variance and Standard Deviation for grouped data sets.
Frequently Asked Questions
Why do we take absolute values in Mean Deviation?
We take absolute values because the sum of deviations directly around the mean is always zero. Absolute values prevent positive and negative deviations from cancelling each other out.
What is the difference between Variance and Standard Deviation?
Variance gives the squared deviation, which changes the unit of measurement. Standard Deviation is the square root of variance, bringing the measure back to the original unit of the data.
How do I choose whether to find Mean Deviation about mean or median?
You should use the measure specified in the question. If the question does not specify, using the mean is standard, but the median minimizes the sum of absolute deviations.
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