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 = 0.25, v2 = - 10.7.
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: - 11.
- Choose a random positive number for the end value: 92.
Formula and calculation:
(v1 - v2) / v1 =
(- 11 - 92) / - 11 =
-103 / - 11 ≈
9.363636363636 ≈
9.36
Although the absolute difference is negative: -103, the relative decrease change is positive: 9.36. 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:
(0.25 - (- 10.7))/|0.25| =
(0.25 + 10.7)/|0.25| =
10.95/0.25 =
10.95 ÷ 0.25 =
10.95 ÷ 0.25 × 100/100 =
(10.95 × 100 ÷ 0.25)/100 =
(1,095 ÷ 0.25)/100 =
4,380/100 =
4,380%
The relative percent decrease change
from the original, initial value 0.25 to the final, end value - 10.7:
= 4,380%
The absolute (actual) difference
0.25 + 10.7 = 10.95
By what percentage has 0.25 decreased?
Answer: By 4,380%
By what percentage is - 10.7 smaller than 0.25?
Answer: By 4,380%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).