In Excel 2010, the QUARTILE function has been replaced by the Quartile.Inc function.
Although it has been replaced, the Quartile function is still available in Excel 2010 (stored in the list of compatibility functions), to allow compatibility with earlier versions of Excel.
However, the Quartile function may not be available in future versions of Excel, so it is advised that you use the Quartile.Inc function if possible.
The Excel QUARTILE function returns a requested quartile of a supplied range of values.
The syntax of the function is:
Where the function arguments are:
array    The range of data values for which you want to calculate the specified quartile. 
quart    An integer between 0 and 4, representing the required quartile. 
If the requested quartile falls between two of the values in the supplied array, Excel interpolates between these values to calculate the quartile value.
Note that the Excel Quartile function is closely related to the Excel Percentile function in that:
The spreadsheet below shows examples of the Excel Quartile function, used to calculate the quartiles of the set of values 06 (stored in cells A1A7 of the example spreadsheet).
Formulas:

Results:

Note that in the above examples:
For further examples of the Excel Quartile function, see the Microsoft Office website.
If you get an error from the Excel Quartile function this is likely to be one of the following:
#NUM!   
Occurs if either:

#VALUE!    Occurs if the supplied value of quart is nonnumeric. 