Application.DStDev (Access)

Estimates the standard deviation across a population sample in a specified set of records (a domain).

For example, you could use the DStDev function in a module to calculate the standard deviation across a set of students' test scores. If domain refers to fewer than two records, or if fewer than two records satisfy criteria, the DStDev function returns a Null, indicating that a standard deviation can't be calculated. You can use the DStDev function to specify criteria in the Criteria row of a select query. For example, you could create a query on an Orders table and a Products table to display all products for which the freight cost fell above the mean plus the standard deviation for freight cost. The Criteria row beneath the Freight field would contain the following expression:

DStDev (Expr, Domain, Criteria)

>(DStDev("[Freight]", "Orders") + DAvg("[Freight]", "Orders"))

Arguments

The following arguments are required:

Expr (String) - An expression that identifies the numeric field on which you want to find the standard deviation. It can be a string expression identifying a field from a table or query, or it can be an expression that performs a calculation on data in that field. In expr, you can include the name of a field in a table, a control on a form, a constant, or a function. If expr includes a function, it can be either built-in or user-defined, but not another domain aggregate or SQL aggregate function.

Domain (String) - A string expression identifying the set of records that constitutes the domain. It can be a table name or a query name for a query that does not require a parameter.

Optional arguments

The following argument is optional

Criteria (String) - An optional string expression used to restrict the range of data on which the DStDev function is performed. For example, criteria is often equivalent to the WHERE clause in an SQL expression, without the word WHERE. If criteria is omitted, the DStDev function evaluates expr against the entire domain. Any field that is included in criteria must also be a field in domain; otherwise, the DStDev function will return a Null.