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 = 199, v2 = 15.2.
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: - 17.
- Choose a random positive number for the end value: 95.
Formula and calculation:
(v1 - v2) / v1 =
(- 17 - 95) / - 17 =
-112 / - 17 ≈
6.588235294118 ≈
6.59
Although the absolute difference is negative: -112, the relative decrease change is positive: 6.59. 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:
(199 - 15.2)/|199| =
183.8/199 =
183.8 ÷ 199 =
183.8 ÷ 199 × 100/100 =
(183.8 × 100 ÷ 199)/100 =
(18,380 ÷ 199)/100 ≈
92.361809045226/100 =
92.361809045226% ≈
92.36%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 199 to the final, end value 15.2:
Rounded off to max. 12 decimal places ≈ 92.361809045226%
Rounded off to max. 2 decimal places ≈ 92.36%
The absolute (actual) difference
199 - 15.2 = 183.8
By what percentage has 199 decreased?
Answer: By ≈ 92.36%
By what percentage is 15.2 smaller than 199?
Answer: By ≈ 92.36%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).