Page 101 - DECO504_STATISTICAL_METHODS_IN_ECONOMICS_ENGLISH

Unit 7: Mean Deviation and Standard Deviation

Notes
∑ fd
Mean deviation from Median δ M = N M

Here, ∑ fd M = 196, N = 100.

196
∴ δ M = 100 = 1.96.

∑ fd
Mean deviation from mean δ = N X
X

f
∑ X
X = ∑ f
fx = 00, 16, 42, 30, 68, 40, 24, 14, 8, 18, 20, 00, 24.
∑ fx = 304, ∑ f = 100

304
∴ X = 100 = 3.04
Deviation from Mean

Item f deviation d X fd X

0 15 |3.04| 45.6
1 16 |2.04| 32.64
2 21 |1.04| 21.84
3 10 |0.04| 0.4
4 17 |0.96| 16.32
5 8 |1.96| 15.68
6 4 |2.96| 11.84
7 2 |3.96| 7.92
8 1 |4.96| 4.96
9 2 |5.96| 11.96
10 2 |6.96| 13.96
11 0 |7.96| 00
12 2 |8.96| 17.92
∑ fd = 201.04
X
∑ fd
Mean deviation δ X = N X

∑ fd X = 201.04, N = 100

201.04
∴ δ X = 100 = 2.01

Answer: Mean deviation from Median δ M is equal to 1.96 whereas that from arithmetic mean
δ = 2.01.
X

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