2.  Measures of central tendency  Measures of central tendency are a combination of two words i.e. ‘measure’ and ‘Central tendency’. Measure means methods and central tendency means average value of any statistical series. Thus we can say that central tendency means the methods of finding out the central value or average value of a statistical series of quantitative information.

3. 1) Mean :

4. X123456789 F35106712151120 XFXF 133 2510 3 30 4624 5735 61272 715105 81188 920180

6. Ex:-2 Find the mean for the following frequency distribution table. Ans: x Class0-1010-2020-3030-4040-5050-60 Frequency404155302116 Class 0-10405-2-80 10-204115-41 20-305525 – a00 30-403035132 40-502145242 50-601655348

8. 2) Median:

11. Marks10-1415-1920-2425-2930-3435-3940-4445-49 No. of students 461057396 MarksNo. of studentsC.F. 10-1444 15-19610 20-241020 25-29525 30-34732 35-39335 40-44944 45-49650

12. 3) Mode: Mode is the value which occurs most frequently in a set of observations. In case of frequency distribution, the value having maximum frequency is mode.  Mode of continuous frequency distribution: In this case of continuous frequency distribution i.e., when the data are given in the class corresponding to the highest frequency is called the model class and the mode can be calculated as follow:

14. Ex:-1 Calculate the mode of the following data. 1, 5, 3, 4, 5, 3, 1, 7, 6, 5, 4, 1, 4, 9, 8, 4. Ans: Observe that the observation 4 occurs maximum times. Thus the mode is 4. Ex:-2 Calculate the mode for the following data. Ans: Here, the highest frequency is 32. corresponding to the class 40-50. Thus, The model class is 40-50. Marks0-1010-2020-3030-4040-5050-6060-70 No. of students51520 3214

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