# WorksheetFunction.Trend (Excel)

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.

If the array known_y's is in a single column, each column of known_x's is interpreted as a separate variable. If the array known_y's is in a single row, 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 use semicolons to separate rows.

**Trend** (Arg1, Arg2, ..., Arg4)

```
Dim arrTrend() As Variant
arrTrend() = WorksheetFunction.Trend(Arg1:=)
```

## Arguments

Arg1, Arg2, ..., Arg4Arg1 - Known_y's - the set of y-values that you already know in the relationship y = mx + b

Arg2 - Known_x's - an optional set of x-values that you may already know in the relationship y = mx + b

Arg3 - New_x's - new x-values for which you want Trend to return corresponding y-values

Arg4 - Const - a logical value specifying whether to force the constant b to equal 0