Question

If Q1 = 12 & Q3 = 20 then Quartile Deviation​

Answer 1

Answer:

The Quartile Deviation

Formally, the Quartile Deviation is equal to the half of the Inter-Quartile Range and thus we can write it as –

Q

d

=

Q

3

–

Q

1

2

Therefore, we also call it the Semi Inter-Quartile Range.

The Quartile Deviation doesn’t take into account the extreme points of the distribution. Thus, the dispersion or the spread of only the central 50% data is considered.

If the scale of the data is changed, the Qd also changes in the same ratio.

It is the best measure of dispersion for open-ended systems (which have open-ended extreme ranges).

Also, it is less affected by sampling fluctuations in the dataset as compared to the range (another measure of dispersion).

Since it is solely dependent on the central values in the distribution, if in any experiment, these values are abnormal or inaccurate, the result would be affected drastically.