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 = 0.05, v2 = 191.3.
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: - 18.
- Choose a random positive number for the end value: 47.
Formula and calculation:
(v1 - v2) / v1 =
(- 18 - 47) / - 18 =
-65 / - 18 ≈
3.611111111111 ≈
3.61
Although the absolute difference is negative: -65, the relative decrease change is positive: 3.61. 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:
(0.05 - 191.3)/|0.05| =
- 191.25/0.05 =
- 191.25 ÷ 0.05 =
- 191.25 ÷ 0.05 × 100/100 =
(- 191.25 × 100 ÷ 0.05)/100 =
(- 19,125 ÷ 0.05)/100 =
- 382,500/100 =
- 382,500%
The relative percent decrease change
from the original, initial value 0.05 to the final, end value 191.3:
= - 382,500%
The absolute (actual) difference
0.05 - 191.3 = - 191.25
By what percentage has 0.05 decreased?
Answer: By - 382,500%
By what percentage is 191.3 smaller than 0.05?
Answer: By - 382,500%
The relative percent decrease change is negative,
so in this case we really have a relative percent increase instead
(the value goes up).