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 = 512, v2 = 161.7.
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: - 35.
- Choose a random positive number for the end value: 96.
Formula and calculation:
(v1 - v2) / v1 =
(- 35 - 96) / - 35 =
-131 / - 35 ≈
3.742857142857 ≈
3.74
Although the absolute difference is negative: -131, the relative decrease change is positive: 3.74. 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:
(512 - 161.7)/|512| =
350.3/512 =
350.3 ÷ 512 =
350.3 ÷ 512 × 100/100 =
(350.3 × 100 ÷ 512)/100 =
(35,030 ÷ 512)/100 =
68.41796875/100 =
68.41796875% ≈
68.42%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 512 to the final, end value 161.7:
Not rounded = 68.41796875%
Rounded off to max. 2 decimal places ≈ 68.42%
The absolute (actual) difference
512 - 161.7 = 350.3
By what percentage has 512 decreased?
Answer: By ≈ 68.42%
By what percentage is 161.7 smaller than 512?
Answer: By ≈ 68.42%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).