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 = 208, v2 = 81.3.
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: - 46.
- Choose a random positive number for the end value: 70.
Formula and calculation:
(v1 - v2) / v1 =
(- 46 - 70) / - 46 =
-116 / - 46 ≈
2.521739130435 ≈
2.52
Although the absolute difference is negative: -116, the relative decrease change is positive: 2.52. 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:
(208 - 81.3)/|208| =
126.7/208 =
126.7 ÷ 208 =
126.7 ÷ 208 × 100/100 =
(126.7 × 100 ÷ 208)/100 =
(12,670 ÷ 208)/100 ≈
60.913461538462/100 =
60.913461538462% ≈
60.91%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 208 to the final, end value 81.3:
Rounded off to max. 12 decimal places ≈ 60.913461538462%
Rounded off to max. 2 decimal places ≈ 60.91%
The absolute (actual) difference
208 - 81.3 = 126.7
By what percentage has 208 decreased?
Answer: By ≈ 60.91%
By what percentage is 81.3 smaller than 208?
Answer: By ≈ 60.91%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).