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 = 7.66, v2 = - 8.8.
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: - 100.
- Choose a random positive number for the end value: 51.
Formula and calculation:
(v1 - v2) / v1 =
(- 100 - 51) / - 100 =
-151 / - 100 =
1.51
Although the absolute difference is negative: -151, the relative decrease change is positive: 1.51. 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:
(7.66 - (- 8.8))/|7.66| =
(7.66 + 8.8)/|7.66| =
16.46/7.66 =
16.46 ÷ 7.66 =
16.46 ÷ 7.66 × 100/100 =
(16.46 × 100 ÷ 7.66)/100 =
(1,646 ÷ 7.66)/100 ≈
214.882506527415/100 =
214.882506527415% ≈
214.88%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 7.66 to the final, end value - 8.8:
Rounded off to max. 12 decimal places ≈ 214.882506527415%
Rounded off to max. 2 decimal places ≈ 214.88%
The absolute (actual) difference
7.66 + 8.8 = 16.46
By what percentage has 7.66 decreased?
Answer: By ≈ 214.88%
By what percentage is - 8.8 smaller than 7.66?
Answer: By ≈ 214.88%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).