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I have this Function

y = (x - min) / (max - min)

which normalizes my values. Now i want to know how to denormalize them, how does the new function look like?

T.Setso
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1 Answers1

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Suppose the minimum is achieved at $x_1$ and the maximum at $x_2$. It is easy to write a linear interpolant: in fact, just use point-slope form:

$$ y - M = \frac{M - m}{x_2 - x_1} \left( x - x_2 \right) $$

and you have a function that returns the raw scores instead of the normalized values.

Sean Roberson
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  • Thanks, but what is M / m? – T.Setso Jan 11 '17 at 17:17
  • Maximum and minimum, respectively. – Sean Roberson Jan 11 '17 at 17:23
  • Hm i didnt understand that, my point is, if i have an array of datas. and i want to to normalize the values of my array between 0 and 1. Example: the minimum value of my array has the value 2, and the maximum value of my array has the value 200, now i want to normalize a value 5: (5 - 2) / (200 - 2). My normalized value = 0,01515. what i want is, to get a function which makes out of my value 0,01515 the value 5. – T.Setso Jan 11 '17 at 17:41
  • This function above does the job. What you're looking for is an inverse function, which can be also found by taking your original function, interchanging $x$ and $y$, then solving for $y$ again. – Sean Roberson Jan 11 '17 at 17:48