## Libraries.Compute.Statistics.Calculations.Moment Documentation

This class calculates the variance of a particular DataFrameColumn. The variance calculated in this case is the sample variance. More information can be found about variance here: https://en.wikipedia.org/wiki/Variance

Example Code

``````use Libraries.Compute.Statistics.DataFrame
use Libraries.Compute.Statistics.Calculations.Variance

//Load a comma separated file
DataFrame frame
Variance variance
variance:SetMean(17) //set the mean before using it
DataFrameColumn column = frame:GetColumn(0)
column:Calculate(variance)
number variance = variance:GetVariance()
``````

## Actions Documentation

If the calculation otherwise has no primitive type, it sends it to the column as a raw object. Columns might use this if they have custom types.

#### Parameters

If the calculation returns true from IsIterable, this is a Boolean object that was passed to the calculation. This may be undefined, which indicates that the column did not contain a value at this position in the column.

#### Parameters

assume the first moment

#### Parameters

If the calculation returns true from IsIterable, this is a Text object that was passed to the calculation. This may be undefined, which indicates that the column did not contain a value at this position in the column.

### Calculate(Libraries.Compute.Statistics.DataFrameColumn column)

This action can calculate the equation from a particular column. By default this action will only be called if the Calculation is not Iterable. Because the Column class is not guaranteed to have any particular data type, individual Calculation classes may need to cast to a particular column or data type to perform their operations. If a calculation is Iterable, the column will pass all of its data, one by one, to the calculation instead.

### Compare(Libraries.Language.Object object)

This action compares two object hash codes and returns an integer. The result is larger if this hash code is larger than the object passed as a parameter, smaller, or equal. In this case, -1 means smaller, 0 means equal, and 1 means larger. This action was changed in Quorum 7 to return an integer, instead of a CompareResult object, because the previous implementation was causing efficiency issues.

#### Return

integer: The Compare result, Smaller, Equal, or Larger.

Example

``````Object o
Object t
integer result = o:Compare(t) //1 (larger), 0 (equal), or -1 (smaller)
``````

### Empty()

This calculation can be used again if Empty is called after using it on a column.

### End(Libraries.Compute.Statistics.DataFrameColumn column)

This action is called at the end of a calculation.

### Equals(Libraries.Language.Object object)

This action determines if two objects are equal based on their hash code values.

#### Return

boolean: True if the hash codes are equal and false if they are not equal.

Example

``````use Libraries.Language.Object
use Libraries.Language.Types.Text
Object o
Text t
boolean result = o:Equals(t)
``````

### GetHashCode()

This action gets the hash code for an object.

#### Return

integer: The integer hash code of the object.

Example

``````Object o
integer hash = o:GetHashCode()
``````

Returns the mean

number:

### GetMoment()

Returns the sample variance.

integer:

### GetResult()

Returns the sample variance.

number:

### GetSize()

Sets the mean. The variance then uses this value in its calculation.

integer:

### IsIterable()

If this action returns true, each element of the column will be sent to this calculation one by one. If this is false, the column should ask this class to conduct the calculation all at once using the Calculate action.

boolean:

### IsNumerical()

If this action returns true, the calculation is numerical, the column must be numerical If this is false, the calculation should be non-numerical, thus the column will not be required to be a numerical column action.

boolean:

### SetMean(number mean)

Sets the mean. The variance then uses this value in its calculation.

• number mean

### SetMoment(integer moment)

#### Parameters

• integer moment

Returns the mean

• integer size

### Start(Libraries.Compute.Statistics.DataFrameColumn column)

assume the first moment