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 = 115.6, v2 = 38.5.
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: - 27.
- Choose a random positive number for the end value: 16.
Formula and calculation:
(v1 - v2) / v1 =
(- 27 - 16) / - 27 =
-43 / - 27 ≈
1.592592592593 ≈
1.59
Although the absolute difference is negative: -43, the relative decrease change is positive: 1.59. 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:
(115.6 - 38.5)/|115.6| =
77.1/115.6 =
77.1 ÷ 115.6 =
77.1 ÷ 115.6 × 100/100 =
(77.1 × 100 ÷ 115.6)/100 =
(7,710 ÷ 115.6)/100 ≈
66.695501730104/100 =
66.695501730104% ≈
66.7%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 115.6 to the final, end value 38.5:
Rounded off to max. 12 decimal places ≈ 66.695501730104%
Rounded off to max. 2 decimal places ≈ 66.7%
The absolute (actual) difference
115.6 - 38.5 = 77.1
By what percentage has 115.6 decreased?
Answer: By ≈ 66.7%
By what percentage is 38.5 smaller than 115.6?
Answer: By ≈ 66.7%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).