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 = - 0.07, v2 = - 18.9.
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: - 57.
- Choose a random positive number for the end value: 75.
Formula and calculation:
(v1 - v2) / v1 =
(- 57 - 75) / - 57 =
-132 / - 57 ≈
2.315789473684 ≈
2.32
Although the absolute difference is negative: -132, the relative decrease change is positive: 2.32. 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:
(- 0.07 - (- 18.9))/|- 0.07| =
(- 0.07 + 18.9)/|- 0.07| =
18.83/0.07 =
18.83 ÷ 0.07 =
18.83 ÷ 0.07 × 100/100 =
(18.83 × 100 ÷ 0.07)/100 =
(1,883 ÷ 0.07)/100 =
26,900/100 =
26,900%
The relative percent decrease change
from the original, initial value - 0.07 to the final, end value - 18.9:
= 26,900%
The absolute (actual) difference
- 0.07 - (- 18.9) = - 0.07 + 18.9 = 18.83
By what percentage has - 0.07 decreased?
Answer: By 26,900%
By what percentage is - 18.9 smaller than - 0.07?
Answer: By 26,900%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).