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 = 12.856, v2 = 2.7.
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: - 58.
- Choose a random positive number for the end value: 97.
Formula and calculation:
(v1 - v2) / v1 =
(- 58 - 97) / - 58 =
-155 / - 58 ≈
2.672413793103 ≈
2.67
Although the absolute difference is negative: -155, the relative decrease change is positive: 2.67. 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:
(12.856 - 2.7)/|12.856| =
10.156/12.856 =
10.156 ÷ 12.856 =
10.156 ÷ 12.856 × 100/100 =
(10.156 × 100 ÷ 12.856)/100 =
(1,015.6 ÷ 12.856)/100 ≈
78.998133167393/100 =
78.998133167393% ≈
79%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 12.856 to the final, end value 2.7:
Rounded off to max. 12 decimal places ≈ 78.998133167393%
Rounded off to max. 2 decimal places ≈ 79%
The absolute (actual) difference
12.856 - 2.7 = 10.156 ≈ 10.16
By what percentage has 12.856 decreased?
Answer: By ≈ 79%
By what percentage is 2.7 smaller than 12.856?
Answer: By ≈ 79%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).