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 = 38.84, v2 = 22.2.
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: - 80.
- Choose a random positive number for the end value: 92.
Formula and calculation:
(v1 - v2) / v1 =
(- 80 - 92) / - 80 =
-172 / - 80 =
2.15
Although the absolute difference is negative: -172, the relative decrease change is positive: 2.15. 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:
(38.84 - 22.2)/|38.84| =
16.64/38.84 =
16.64 ÷ 38.84 =
16.64 ÷ 38.84 × 100/100 =
(16.64 × 100 ÷ 38.84)/100 =
(1,664 ÷ 38.84)/100 =
42.842430484037/100 =
42.842430484037% ≈
42.84%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 38.84 to the final, end value 22.2:
Not rounded = 42.842430484037%
Rounded off to max. 2 decimal places ≈ 42.84%
The absolute (actual) difference
38.84 - 22.2 = 16.64
By what percentage has 38.84 decreased?
Answer: By ≈ 42.84%
By what percentage is 22.2 smaller than 38.84?
Answer: By ≈ 42.84%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).