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 = 130, v2 = 88.1.
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: - 56.
- Choose a random positive number for the end value: 23.
Formula and calculation:
(v1 - v2) / v1 =
(- 56 - 23) / - 56 =
-79 / - 56 ≈
1.410714285714 ≈
1.41
Although the absolute difference is negative: -79, the relative decrease change is positive: 1.41. 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:
(130 - 88.1)/|130| =
41.9/130 =
41.9 ÷ 130 =
41.9 ÷ 130 × 100/100 =
(41.9 × 100 ÷ 130)/100 =
(4,190 ÷ 130)/100 ≈
32.230769230769/100 =
32.230769230769% ≈
32.23%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 130 to the final, end value 88.1:
Rounded off to max. 12 decimal places ≈ 32.230769230769%
Rounded off to max. 2 decimal places ≈ 32.23%
The absolute (actual) difference
130 - 88.1 = 41.9
By what percentage has 130 decreased?
Answer: By ≈ 32.23%
By what percentage is 88.1 smaller than 130?
Answer: By ≈ 32.23%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).