Data transformations

39

8

Data transformations

The values in the Working Data grid can be transformed using a variety of

functions. From the working data window select 

Transform

 in the 

Type of

Adjustment

 panel.

The possible relative measures available within 

CAP 

are given below. Select the

transformation to be made and click on 

Submit

 to make the change.  The

transformation options within 

CAP

 are itemised below.

Reload raw data

   This will cause the working data to revert to the raw data.

Log(10)

   Each value is transformed to the log to base 10. This cannot be done

for numbers <= 0.

Log10(x+1)

   Each value is transformed by adding 1 and then calculating the log

to base 10. This is used when the data contains zero values.

Log e 

  Each value is transformed to the log to base e (natural logs). This cannot

be done for numbers <= 0.

Log e (x+1)

   Each value is transformed by adding 1 and then calculating the log

to base e. This is used when the data contains zero values.

Square root

   the square root of each number is calculated. This cannot be done

for negative numbers.

Arcsin

   The Arcsin of each value is calculated. A transformation often used for

percentage data.

Arcsin root

   The Arcsin of the square root of each number is calculated.

Power

   Each value, x, is transformed to xa, where a is chosen by the user.

Add constant

   A constant value, chosen by the user, is added to each value.

Subtract constant

   A constant value, chosen by the user is subtracted from

each value.

Multiply by constant

   Each value is multiplied by a constant value chosen by

the user.

Divide by constant 

  Each value is divided by a constant value chosen by the

user.

8.1

Dealing with zeros

Rows or columns in the working data holding zero values can be removed. On

the Working Data page select 

Handling zeros

 in the 

Type of Adjustment

 panel.

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