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 = 380, v2 = 301.3.
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: - 8.
- Choose a random positive number for the end value: 99.
Formula and calculation:
(v1 - v2) / v1 =
(- 8 - 99) / - 8 =
-107 / - 8 =
13.375 ≈
13.38
Although the absolute difference is negative: -107, the relative decrease change is positive: 13.38. 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:
(380 - 301.3)/|380| =
78.7/380 =
78.7 ÷ 380 =
78.7 ÷ 380 × 100/100 =
(78.7 × 100 ÷ 380)/100 =
(7,870 ÷ 380)/100 ≈
20.710526315789/100 =
20.710526315789% ≈
20.71%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 380 to the final, end value 301.3:
Rounded off to max. 12 decimal places ≈ 20.710526315789%
Rounded off to max. 2 decimal places ≈ 20.71%
The absolute (actual) difference
380 - 301.3 = 78.7
By what percentage has 380 decreased?
Answer: By ≈ 20.71%
By what percentage is 301.3 smaller than 380?
Answer: By ≈ 20.71%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).