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 = 94, v2 = 75.5.
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: 94.
Formula and calculation:
(v1 - v2) / v1 =
(- 63 - 94) / - 63 =
-157 / - 63 ≈
2.492063492063 ≈
2.49
Although the absolute difference is negative: -157, the relative decrease change is positive: 2.49. 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:
(94 - 75.5)/|94| =
18.5/94 =
18.5 ÷ 94 =
18.5 ÷ 94 × 100/100 =
(18.5 × 100 ÷ 94)/100 =
(1,850 ÷ 94)/100 ≈
19.68085106383/100 =
19.68085106383% ≈
19.68%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 94 to the final, end value 75.5:
Rounded off to max. 12 decimal places ≈ 19.68085106383%
Rounded off to max. 2 decimal places ≈ 19.68%
The absolute (actual) difference
94 - 75.5 = 18.5
By what percentage has 94 decreased?
Answer: By ≈ 19.68%
By what percentage is 75.5 smaller than 94?
Answer: By ≈ 19.68%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).