AP EAMCET Engineering 20 Apr 2019 Shift 2 Paper

The expression for the coefficient of variance is given by,
CV=‌‌

σ

µ

×100
Therefore,
60=‌‌

21

µ

×100
µ=‌‌

21×10

6

=35
The new mean on addition of 15 to every observation is,
µ′=35+15
=50
But
∑|µ′−xi′|=∑|µ−xi|
Now
21=√‌‌

∑(µ−xi)2

n

212=‌‌

∑(µ−xi)2

n

∑(µ−xi)2=212×n
Thus,
σ′=√‌‌

∑(µ′−xi′)2

n

=√‌‌

212×n

n

=21
Therefore, the new coefficient of variance is
CVNew=‌‌

21

50

×100
=42