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 = 2.66, v2 = - 39.5.
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: - 89.
- Choose a random positive number for the end value: 27.
Formula and calculation:
(v1 - v2) / v1 =
(- 89 - 27) / - 89 =
-116 / - 89 ≈
1.303370786517 ≈
1.3
Although the absolute difference is negative: -116, the relative decrease change is positive: 1.3. 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:
(2.66 - (- 39.5))/|2.66| =
(2.66 + 39.5)/|2.66| =
42.16/2.66 =
42.16 ÷ 2.66 =
42.16 ÷ 2.66 × 100/100 =
(42.16 × 100 ÷ 2.66)/100 =
(4,216 ÷ 2.66)/100 ≈
1,584.962406015038/100 =
1,584.962406015038% ≈
1,584.96%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 2.66 to the final, end value - 39.5:
Rounded off to max. 12 decimal places ≈ 1,584.962406015038%
Rounded off to max. 2 decimal places ≈ 1,584.96%
The absolute (actual) difference
2.66 + 39.5 = 42.16
By what percentage has 2.66 decreased?
Answer: By ≈ 1,584.96%
By what percentage is - 39.5 smaller than 2.66?
Answer: By ≈ 1,584.96%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).