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# WorksheetFunction.Trend Method

Office 2007
Returns values along a linear trend. Fits a straight line (using the method of least squares) to the arrays known_y's and known_x's. Returns the y-values along that line for the array of new_x's that you specify.

Syntax

expression.Trend(Arg1, Arg2, Arg3, Arg4)

expression   A variable that represents a WorksheetFunction object.

Parameters

NameRequired/OptionalData TypeDescription
Arg1RequiredVariantKnown_y's - the set of y-values you already know in the relationship y = mx + b.
Arg2OptionalVariantKnown_x's - an optional set of x-values that you may already know in the relationship y = mx + b.
Arg3OptionalVariantNew_x's - new x-values for which you want TREND to return corresponding y-values.
Arg4OptionalVariantConst - a logical value specifying whether to force the constant b to equal 0.

Return Value
Variant

Remarks

• If the array known_y's is in a single column, then each column of known_x's is interpreted as a separate variable.
• If the array known_y's is in a single row, then each row of known_x's is interpreted as a separate variable.
• The array known_x's can include one or more sets of variables. If only one variable is used, known_y's and known_x's can be ranges of any shape, as long as they have equal dimensions. If more than one variable is used, known_y's must be a vector (that is, a range with a height of one row or a width of one column).
• If known_x's is omitted, it is assumed to be the array {1,2,3,...} that is the same size as known_y's.
• New_x's must include a column (or row) for each independent variable, just as known_x's does. So, if known_y's is in a single column, known_x's and new_x's must have the same number of columns. If known_y's is in a single row, known_x's and new_x's must have the same number of rows.
• If you omit new_x's, it is assumed to be the same as known_x's.
• If you omit both known_x's and new_x's, they are assumed to be the array {1,2,3,...} that is the same size as known_y's.
• If const is TRUE or omitted, b is calculated normally.
• If const is FALSE, b is set equal to 0 (zero), and the m-values are adjusted so that y = mx.
• For information about how Microsoft Excel fits a line to data, see LINEST.
• You can use TREND for polynomial curve fitting by regressing against the same variable raised to different powers. For example, suppose column A contains y-values and column B contains x-values. You can enter x^2 in column C, x^3 in column D, and so on, and then regress columns B through D against column A.
• Formulas that return arrays must be entered as array formulas.
• When entering an array constant for an argument such as known_x's, use commas to separate values in the same row and semicolons to separate rows.