The Excel Dstdevp function calculates the standard deviation of a field (column) in a database for selected records only. The records to be included in the calculation are defined by a set of one or more userspecified criteria.
The syntax of the function is :
where the arguments are shown in the table below:
database    A range of cells containing the database. The top row of the database should specify the field names.  
field   
The field (column) within the database, for which the standard deviation is to be calculated.
This can either be a field number, or it can be the field name (ie. the header in the top row of the database) encased in quotes (eg. "Subject", "Name", etc) 

criteria   
A range of cells that contain the criteria, to specify which records should be included in the calculation.
The range can include one or more criteria, which are presented as a field name in one cell and the condition for that field in the cell below. eg.

Wildcards
You can also use the following wildcards in textrelated criteria:
?  matches any single character
*  matches any sequence of characters
if you do actually want to find the ? or * character, type the ~ symbol before this character in your search.
eg. the condition "A*e" will match all cells containing a text string beginning with "A" and ending in "e".The criteria supplied beneath each field heading can be either:
  a numeric value (including an integer, decimal, date, time, or logical value) (eg. 10, 01/01/2011, FALSE)  
or  
  a text string (eg. "Text", "Monday")  
or  
  an expression (eg. ">8", "<>0") 
Note that the Excel database functions are not case sensitive. So, for example, the criteria ="Name" will be satisfied by cells containing the text "Name" or "name".
A  B  C  D  E  

1  Name  Gender  Age  Subject  Score 
2  Amy  Female  10  Math  63% 
3  Amy  Female  10  English  78% 
4  Amy  Female  10  Science  39% 
5  Bill  Male  8  Math  55% 
6  Bill  Male  8  English  71% 
7  Bill  Male  8  Science  51% 
8  Sam  Male  9  Math  39% 
9  Sam  Male  9  English  52% 
10  Sam  Male  9  Science  48% 
11  Tom  Male  9  Math  78% 
12  Tom  Male  9  English  69% 
13  Tom  Male  9  Science  65% 
The following examples are based on the simple database on the right, which stores the examination marks scored by four children in three different subjects.
In the example below, the Dstdevp function is used to find the standard deviation of scores obtained in English, by male students. The criteria are specified in cells G1  H2 and the Dstdev formula is shown in cell G3.
G  H  

1  Subject  Gender 
2  English  Male 
3  =DSTDEVP( A1:E13, "Score", G1:H2 ) 
The above Dstdevp function calculates the standard deviation of the values in cells E6, E9 & E12, and therefore returns the value 8.5%.
In the example below, the Dstdevp function is used to find the standard deviation for the Math scores obtained by students over 8 years of age.
G  H  

1  Subject  Age 
2  Math  >8 
3  =DSTDEVP( A1:E13, "Score", G1:H2 ) 
The above Dstdevp function finds the standard deviation of the values in cells E2, E8 & E11 and so returns the value 16.1%.
Note that, in the above two examples, instead of typing in "Score" for the field argument, we could have simply used the number 5 (to denote the 5th column of the database).
Further examples of the Excel Dstdevp function can be found on the Microsoft Office website.