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 = 9.64, v2 = 2.1.
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: - 63.
- Choose a random positive number for the end value: 48.
Formula and calculation:
(v1 - v2) / v1 =
(- 63 - 48) / - 63 =
-111 / - 63 ≈
1.761904761905 ≈
1.76
Although the absolute difference is negative: -111, the relative decrease change is positive: 1.76. 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:
(9.64 - 2.1)/|9.64| =
7.54/9.64 =
7.54 ÷ 9.64 =
7.54 ÷ 9.64 × 100/100 =
(7.54 × 100 ÷ 9.64)/100 =
(754 ÷ 9.64)/100 ≈
78.215767634855/100 =
78.215767634855% ≈
78.22%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 9.64 to the final, end value 2.1:
Rounded off to max. 12 decimal places ≈ 78.215767634855%
Rounded off to max. 2 decimal places ≈ 78.22%
The absolute (actual) difference
9.64 - 2.1 = 7.54
By what percentage has 9.64 decreased?
Answer: By ≈ 78.22%
By what percentage is 2.1 smaller than 9.64?
Answer: By ≈ 78.22%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).