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 = 1.8, v2 = - 2.2.
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: - 41.
- Choose a random positive number for the end value: 92.
Formula and calculation:
(v1 - v2) / v1 =
(- 41 - 92) / - 41 =
-133 / - 41 ≈
3.243902439024 ≈
3.24
Although the absolute difference is negative: -133, the relative decrease change is positive: 3.24. 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:
(1.8 - (- 2.2))/|1.8| =
(1.8 + 2.2)/|1.8| =
4/1.8 =
4 ÷ 1.8 =
4 ÷ 1.8 × 100/100 =
(4 × 100 ÷ 1.8)/100 =
(400 ÷ 1.8)/100 ≈
222.222222222222/100 =
222.222222222222% ≈
222.22%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 1.8 to the final, end value - 2.2:
Rounded off to max. 12 decimal places ≈ 222.222222222222%
Rounded off to max. 2 decimal places ≈ 222.22%
The absolute (actual) difference
1.8 + 2.2 = 4
By what percentage has 1.8 decreased?
Answer: By ≈ 222.22%
By what percentage is - 2.2 smaller than 1.8?
Answer: By ≈ 222.22%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).