Question

Standard Deviation
itual Series
Calculate standard deviation (use direct method) and coefficient of standard deviation from the following
data on marks obtained by 6 students in a class test. 14, 12, 16, 20, 18, 22 ​

Answer 1

Explanation:

x= 14 12 16 20 18 22 =102

x2=196 144 256 400 324 484 =1804

• Am=102÷6=17

• SD=
• $\sqrt{1804 \div 6 - 17 {?}^{2} }$
• $\sqrt{300.666 - 289}$
• =3.4155

CV=SD/AM ×100

=3.4155/17×100

=0.2009×100

=20.0911

Answer 2

Given:

Marks - 14, 12, 16, 20, 18, 22 ​

To Find:

Standard deviation of the marks

Explanation:

x = 14 12 16 20 18 22

  = 102

x₂ = 196 144 256 400 324 484

   = 1804

Am= (102/6)

     = 17

SD = √180/6 - 17²

     = √300.666 - 289

    = 3.4155