The relative decrease change. Definition:
The relative decrease change is the difference in an indicator over two periods in time, v1 - v2, relative to the value of the indicator in the earlier period, v1.
- Where:
- v1 - is called the reference value (original, initial number);
- v2 - is called the new value (the end value).
- In our case: v1 = 22, v2 = 7.1.
The relative decrease change. Formula:
The relative decrease change =
The actual change / |v1|
(v1 - v2) / |v1| =
- Legend:
- v1 - the original number
- |v1| - the positive value of v1, |v1| >= 0. By example: |10| = 10; |-10| = 10.
- v2 - the new value
- The actual change = v1 - v2
- / - the fraction bar (division)
Why do we use |v1| in the formula instead of v1?
- Let's see what happens if we use v1 instead of |v1|:
- Choose a random negative number as the initial value: - 9.
- Choose a random positive number for the end value: 38.
Formula and calculation:
(v1 - v2) / v1 =
(- 9 - 38) / - 9 =
-47 / - 9 ≈
5.222222222222 ≈
5.22
Although the absolute difference is negative: -47, the relative decrease change is positive: 5.22. By using |v1| instead of v1, the error is corrected.
The relative percent decrease change. Detailed calculations below
By multiplying a number by the fraction 100/100,
we change only the form of the result, not the result.
- 100/100 = 100% = 100 ÷ 100 = 1.
- n × 100/100 = (n × 100)/100 = (n × 100)%, any number.
The relative percent decrease change. Formula:
The relative percent decrease change =
The relative decrease change × 100/100 =
(The relative decrease change × 100)/100 =
(The relative decrease change × 100)%
Calculate the relative percent decrease change:
(22 - 7.1)/|22| =
14.9/22 =
14.9 ÷ 22 =
14.9 ÷ 22 × 100/100 =
(14.9 × 100 ÷ 22)/100 =
(1,490 ÷ 22)/100 ≈
67.727272727273/100 =
67.727272727273% ≈
67.73%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 22 to the final, end value 7.1:
Rounded off to max. 12 decimal places ≈ 67.727272727273%
Rounded off to max. 2 decimal places ≈ 67.73%
The absolute (actual) difference
22 - 7.1 = 14.9
By what percentage has 22 decreased?
Answer: By ≈ 67.73%
By what percentage is 7.1 smaller than 22?
Answer: By ≈ 67.73%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).