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 = 57, v2 = 48.7.
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: - 40.
- Choose a random positive number for the end value: 58.
Formula and calculation:
(v1 - v2) / v1 =
(- 40 - 58) / - 40 =
-98 / - 40 =
2.45
Although the absolute difference is negative: -98, the relative decrease change is positive: 2.45. 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:
(57 - 48.7)/|57| =
8.3/57 =
8.3 ÷ 57 =
8.3 ÷ 57 × 100/100 =
(8.3 × 100 ÷ 57)/100 =
(830 ÷ 57)/100 ≈
14.561403508772/100 =
14.561403508772% ≈
14.56%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 57 to the final, end value 48.7:
Rounded off to max. 12 decimal places ≈ 14.561403508772%
Rounded off to max. 2 decimal places ≈ 14.56%
The absolute (actual) difference
57 - 48.7 = 8.3
By what percentage has 57 decreased?
Answer: By ≈ 14.56%
By what percentage is 48.7 smaller than 57?
Answer: By ≈ 14.56%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).