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 = 85, v2 = 73.5.
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: - 62.
- Choose a random positive number for the end value: 95.
Formula and calculation:
(v1 - v2) / v1 =
(- 62 - 95) / - 62 =
-157 / - 62 ≈
2.532258064516 ≈
2.53
Although the absolute difference is negative: -157, the relative decrease change is positive: 2.53. 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:
(85 - 73.5)/|85| =
11.5/85 =
11.5 ÷ 85 =
11.5 ÷ 85 × 100/100 =
(11.5 × 100 ÷ 85)/100 =
(1,150 ÷ 85)/100 ≈
13.529411764706/100 =
13.529411764706% ≈
13.53%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 85 to the final, end value 73.5:
Rounded off to max. 12 decimal places ≈ 13.529411764706%
Rounded off to max. 2 decimal places ≈ 13.53%
The absolute (actual) difference
85 - 73.5 = 11.5
By what percentage has 85 decreased?
Answer: By ≈ 13.53%
By what percentage is 73.5 smaller than 85?
Answer: By ≈ 13.53%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).