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 = 27.9, v2 = 7.3.
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: - 3.
- Choose a random positive number for the end value: 80.
Formula and calculation:
(v1 - v2) / v1 =
(- 3 - 80) / - 3 =
-83 / - 3 ≈
27.666666666667 ≈
27.67
Although the absolute difference is negative: -83, the relative decrease change is positive: 27.67. 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:
(27.9 - 7.3)/|27.9| =
20.6/27.9 =
20.6 ÷ 27.9 =
20.6 ÷ 27.9 × 100/100 =
(20.6 × 100 ÷ 27.9)/100 =
(2,060 ÷ 27.9)/100 ≈
73.835125448029/100 =
73.835125448029% ≈
73.84%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 27.9 to the final, end value 7.3:
Rounded off to max. 12 decimal places ≈ 73.835125448029%
Rounded off to max. 2 decimal places ≈ 73.84%
The absolute (actual) difference
27.9 - 7.3 = 20.6
By what percentage has 27.9 decreased?
Answer: By ≈ 73.84%
By what percentage is 7.3 smaller than 27.9?
Answer: By ≈ 73.84%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).