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LOGIT
Computes the logit transformation, including its inverse.
Syntax
LOGIT(X, Return_type)
X
the real number for which we compute the transformation. X must be between 0 and 1 (exclusive).
Return_type is a number that determines the type of return value: 1 (or missing)= Logit , 2= Inverse Logit.
RETURN_TYPE  NUMBER RETURNED 

1 or omitted  Logit Transform 
2  Inverse of Logit transform 
Remarks
 The logit link function is very commonly used for parameters that lie in the unit interval. Numerical values of theta close to 0 or 1 or out of range result in #VALUE! or #N/A.

The logit transformation is defined as follows:
And
Where:
 is the input value of the input time series at time . X must be between 0 and 1, exclusive
 is the transformed logit value at time
 is the inverse logit transformation
 The logit function accepts a single value or an array of values for X.
Examples
Example 1:
A  B  C  D  

1  Date  Data  
2  January 10, 2008  0.66  0.64  0.66 
3  January 11, 2008  0.02  3.99  0.02 
4  January 12, 2008  0.54  0.18  0.54 
5  January 13, 2008  0.21  1.34  0.21 
6  January 14, 2008  0.73  1.02  0.73 
7  January 15, 2008  0.37  0.52  0.37 
8  January 16, 2008  1.00  6.25  1.00 
9  January 17, 2008  0.42  0.32  0.42 
10  January 18, 2008  0.99  5.27  0.99 
11  January 19, 2008  0.04  3.22  0.04 
12  January 20, 2008  0.23  1.20  0.23 
13  January 21, 2008  0.31  0.79  0.31 
14  January 22, 2008  0.69  0.82  0.69 
15  January 23, 2008  0.37  0.54  0.37 
16  January 24, 2008  0.78  1.28  0.78 
17  January 25, 2008  0.30  0.86  0.30 
18  January 26, 2008  0.97  3.45  0.97 
19  January 27, 2008  0.91  2.29  0.91 
20  January 28, 2008  0.92  2.40  0.92 
21  January 29, 2008  0.88  1.97  0.88 
22  January 30, 2008  0.14  1.78  0.14 
23  January 31, 2008  0.06  2.81  0.06 
24  February 1, 2008  0.19  1.42  0.19 
25  February 2, 2008  0.61  0.46  0.61 
Files Examples
References
 Hamilton, J .D.; Time Series Analysis , Princeton University Press (1994), ISBN 0691042896
 Tsay, Ruey S.; Analysis of Financial Time Series John Wiley & SONS. (2005), ISBN 0471690740