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 = 2,905, v2 = 2,417.6.
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: - 83.
- Choose a random positive number for the end value: 100.
Formula and calculation:
(v1 - v2) / v1 =
(- 83 - 100) / - 83 =
-183 / - 83 ≈
2.204819277108 ≈
2.2
Although the absolute difference is negative: -183, the relative decrease change is positive: 2.2. 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:
(2,905 - 2,417.6)/|2,905| =
487.4/2,905 =
487.4 ÷ 2,905 =
487.4 ÷ 2,905 × 100/100 =
(487.4 × 100 ÷ 2,905)/100 =
(48,740 ÷ 2,905)/100 ≈
16.777969018933/100 =
16.777969018933% ≈
16.78%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 2,905 to the final, end value 2,417.6:
Rounded off to max. 12 decimal places ≈ 16.777969018933%
Rounded off to max. 2 decimal places ≈ 16.78%
The absolute (actual) difference
2,905 - 2,417.6 = 487.4
By what percentage has 2,905 decreased?
Answer: By ≈ 16.78%
By what percentage is 2,417.6 smaller than 2,905?
Answer: By ≈ 16.78%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).