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 = 8.31, v2 = 5.3.
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: - 18.
- Choose a random positive number for the end value: 10.
Formula and calculation:
(v1 - v2) / v1 =
(- 18 - 10) / - 18 =
-28 / - 18 ≈
1.555555555556 ≈
1.56
Although the absolute difference is negative: -28, the relative decrease change is positive: 1.56. 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:
(8.31 - 5.3)/|8.31| =
3.01/8.31 =
3.01 ÷ 8.31 =
3.01 ÷ 8.31 × 100/100 =
(3.01 × 100 ÷ 8.31)/100 =
(301 ÷ 8.31)/100 ≈
36.221419975933/100 =
36.221419975933% ≈
36.22%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 8.31 to the final, end value 5.3:
Rounded off to max. 12 decimal places ≈ 36.221419975933%
Rounded off to max. 2 decimal places ≈ 36.22%
The absolute (actual) difference
8.31 - 5.3 = 3.01
By what percentage has 8.31 decreased?
Answer: By ≈ 36.22%
By what percentage is 5.3 smaller than 8.31?
Answer: By ≈ 36.22%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).