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GeographyClass 12them comprehensible. It facilitates data processing. A number of statistical

them comprehensible. It facilitates data processing. A number of statistical | Class 12 Geography Notes

By ConceptScroll Team · Published on 17 July 2026 · 3 min read

them comprehensible. It facilitates data processing. A number of statistical – this guide gives you a concise, exam-ready overview of them comprehensible. It facilitates data processing. A number of statistical from Class 12 Geography, written by ConceptScroll editors and reviewed against the latest NCERT textbook.

Measures of Central Tendency

Measures of central tendency are statistical tools used to find a single value that best represents a set of observations. These values typically lie near the center of the data distribution and serve as representative figures for the entire data set. Such measures are essential when dealing with varying characteristics like rainfall, elevation, population density, educational attainment, or age groups. The main types of measures of central tendency are mean, median, and mode. Each measure provides a different method to determine a central value suited to different types of data sets. The mean is the arithmetic average, the median is the middle value in an ordered data set, and the mode is the most frequently occurring value.

📊 Diagram: No specific diagram in this section, but the concept is foundational for subsequent sections on mean, median, and mode.

🔗 Connection: This section sets the stage for detailed computation methods of mean, median, and mode in the following sections.

Frequently asked questions

1. Choose the correct answer from the four alternatives given below: (i) The measure of central tendency that does not get affected by extreme values: (a) Mean (b) Mean and Mode (c) Mode (d) Median (ii) The measure of central tendency always coinciding with the hump of any distribution is: (a) Median (b) Median and Mode (c) Mean (d) Mode

(i) The measure of central tendency that does not get affected by extreme values is the Median (d). Mean is affected by extreme values, Mode is not necessarily unaffected. Median is resistant to extreme values.

(ii) The measure of central tendency always coinciding with the hump of any distribution is the Mode (d). The Mode is the value that appears most frequently and corresponds to the peak (hump) of the distribution.

2. Answer the following questions in about 30 words: (i) Define the mean. (ii) What are the advantages of using mode?

(i) Mean is the sum of all observations divided by the number of observations. It represents the average value of the data set.

(ii) Advantages of mode:

  • It is easy to understand and calculate.
  • It can be used for qualitative data.
  • It represents the most common value in the data set.
  • It is not affected by extreme values.
3. Answer the following questions in about 125 words: (i) Explain relative positions of mean, median and mode in a normal distribution and skewed distribution with the help of diagrams. (ii) Comment on the applicability of mean, median and mode (hint: from their merits and demerits).

(i) In a normal distribution, mean = median = mode, all three measures coincide at the center of the symmetric bell-shaped curve.

In a positively skewed distribution, mode < median < mean. The tail is stretched to the right, so mean is pulled towards higher values.

In a negatively skewed distribution, mean < median < mode. The tail is stretched to the left, so mean is pulled towards lower values.

Diagrams typically show the bell curve for normal distribution and skewed curves with shifted pea

Activity 1. Take an imaginary example applicable to geographical analysis and explain direct and indirect methods of calculating mean from ungrouped data.

Direct Method: Suppose the data set of ungrouped data is: 5, 7, 9, 10, 12. Mean = (5 + 7 + 9 + 10 + 12) / 5 = 43 / 5 = 8.6

Indirect Method: Choose an assumed mean (A), say 9. Calculate deviations d = x - A: (-4, -2, 0, 1, 3) Sum of deviations Σd = (-4) + (-2) + 0 + 1 + 3 = -2 Mean = A + (Σd / n) = 9 + (-2/5) = 9 - 0.4 = 8.6

Both methods yield the same mean value.

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