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 = 428, v2 = 226.2.
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: - 74.
- Choose a random positive number for the end value: 78.
Formula and calculation:
(v1 - v2) / v1 =
(- 74 - 78) / - 74 =
-152 / - 74 =
2.054054054054 ≈
2.05
Although the absolute difference is negative: -152, the relative decrease change is positive: 2.05. 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:
(428 - 226.2)/|428| =
201.8/428 =
201.8 ÷ 428 =
201.8 ÷ 428 × 100/100 =
(201.8 × 100 ÷ 428)/100 =
(20,180 ÷ 428)/100 ≈
47.14953271028/100 =
47.14953271028% ≈
47.15%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 428 to the final, end value 226.2:
Rounded off to max. 12 decimal places ≈ 47.14953271028%
Rounded off to max. 2 decimal places ≈ 47.15%
The absolute (actual) difference
428 - 226.2 = 201.8
By what percentage has 428 decreased?
Answer: By ≈ 47.15%
By what percentage is 226.2 smaller than 428?
Answer: By ≈ 47.15%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).