THIS PRESENTATION EXPLAINS MEAN DEVIATION IN A STEP BY STEP , EASY WAY. PROBLEM FOR A DISCRETE AND GROUPED FREQUENCY DISTRIBUTION IS DISCUSSED. IT WOULD BE USEFUL TO GRADE 11 MATH STUDENTS AND COLLEGE STUDENTS STUDYING STATISTICS. IT IS ACCOMPANIED BY A VIDEO.

1. MEAN DEVIATION
(GRADE 11 MATH
COLLEGE MATH)

2. Mean Deviation is of 2 types
Mean Deviation about the mean
Mean Deviation about the median
Mean Deviation about the mean is used to measure how the data is
scattered about the mean.
Mean Deviation about the mean =

3. Find the mean Deviation about the mean
1,3,7,9,10,12
1 6
3 4
7 0
9 2
10 3
12 5
20

4. Mean Deviation about the median is used to determine how the data is
scattered around the median.
Mean Deviation about the median =

5. Find the mean Deviation about the median
3,6,11,12,18
3 8
6 5
11 0
12 1
18 7
21

6. For a grouped frequency distribution
Mean Deviation about mean =

7. Find mean Deviation about the mean
1 3
3 3
5 4
7 14
9 7
11 4
13 3
15 4

8. 3 7 21
9 5 15
20 3 12
98 1 14
63 1 7
44 3 12
39 5 15
60 7 28

9. Mean Deviation about mean =

10. Find the mean Deviation about median
15 21 27 30 35
3 5 6 7 8

11. We first calculate the cumulative frequency
15 3 3 15 45
21 5 8 9 45
27 6 14 3 18
30 7 21 0 0
35 8 29 5 40
29 148

12. Mean Deviation about median=

13. Find the mean Deviation about the mean
10- 20 20 -30 30-49 40-50 50-60 60-70 70-80
2 3 8 14 8 3 3

14. Marks f
10-20 2 15 30 30 60
20-30 3 25 75 20 60
30-40 8 35 280 10 80
40-50 14 45 630 0 0
50-60 8 55 440 10 80
60-70 3 65 195 20 60
70-80 2 75 150 30 60
40 1800 400

16. Find the mean Deviation about the median
C i f
0-6 4
6-12 5
12-18 3
18-24 6
24-30 2

17. C I
0-6 4 3 4 12 48
6-12 5 9 9 6 30
12-18 3 15 12 0 0
18-24 6 21 18 6 36
24-30 2 27 20 12 24
20 138

18. Mean Deviation about the median

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