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 = - 1, v2 = - 32.
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: - 55.
- Choose a random positive number for the end value: 1.
Formula and calculation:
(v1 - v2) / v1 =
(- 55 - 1) / - 55 =
-56 / - 55 ≈
1.018181818182 ≈
1.02
Although the absolute difference is negative: -56, the relative decrease change is positive: 1.02. 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:
(- 1 - (- 32))/|- 1| =
(- 1 + 32)/|- 1| =
31/1 =
31 ÷ 1 =
31 ÷ 1 × 100/100 =
(31 × 100 ÷ 1)/100 =
(3,100 ÷ 1)/100 =
3,100/100 =
3,100%
The relative percent decrease change
from the original, initial value - 1 to the final, end value - 32:
= 3,100%
The absolute (actual) difference
- 1 - (- 32) = - 1 + 32 = 31
By what percentage has - 1 decreased?
Answer: By 3,100%
By what percentage is - 32 smaller than - 1?
Answer: By 3,100%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).