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 = 14.9, v2 = 4.1.
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: - 98.
- Choose a random positive number for the end value: 85.
Formula and calculation:
(v1 - v2) / v1 =
(- 98 - 85) / - 98 =
-183 / - 98 ≈
1.867346938776 ≈
1.87
Although the absolute difference is negative: -183, the relative decrease change is positive: 1.87. 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:
(14.9 - 4.1)/|14.9| =
10.8/14.9 =
10.8 ÷ 14.9 =
10.8 ÷ 14.9 × 100/100 =
(10.8 × 100 ÷ 14.9)/100 =
(1,080 ÷ 14.9)/100 =
72.48322147651/100 =
72.48322147651% ≈
72.48%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 14.9 to the final, end value 4.1:
Not rounded = 72.48322147651%
Rounded off to max. 2 decimal places ≈ 72.48%
The absolute (actual) difference
14.9 - 4.1 = 10.8
By what percentage has 14.9 decreased?
Answer: By ≈ 72.48%
By what percentage is 4.1 smaller than 14.9?
Answer: By ≈ 72.48%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).