WorksheetFunction.Slope Method
Returns the slope of the linear regression line through data points in known_y's and known_x's. The slope is the vertical distance divided by the horizontal distance between any two points on the line, which is the rate of change along the regression line.
Namespace: Microsoft.Office.Interop.Excel
Assembly: Microsoft.Office.Interop.Excel (in Microsoft.Office.Interop.Excel.dll)
Syntax
'Declaration
Function Slope ( _
Arg1 As Object, _
Arg2 As Object _
) As Double
'Usage
Dim instance As WorksheetFunction
Dim Arg1 As Object
Dim Arg2 As Object
Dim returnValue As Double
returnValue = instance.Slope(Arg1, Arg2)
double Slope(
Object Arg1,
Object Arg2
)
Parameters
Arg1
Type: System.ObjectKnown_y's - an array or cell range of numeric dependent data points.
Arg2
Type: System.ObjectKnown_x's - the set of independent data points.
Return Value
Type: System.Double
Remarks
The arguments must be either numbers or names, arrays, or references that contain numbers.
If an array or reference argument contains text, logical values, or empty cells, those values are ignored; however, cells with the value zero are included.
If known_y's and known_x's are empty or have a different number of data points, Slope returns the #N/A error value.
The equation for the slope of the regression line is:
Figure 1: Equation for the slope of the regression line
.jpg "Equation for the slope of the regression line")
The underlying algorithm used in the Slope and Intercept(Object, Object) functions is different than the underlying algorithm used in the LinEst(Object, Object, Object, Object) function. The difference between these algorithms can lead to different results when data is undetermined and collinear. For example, if the data points of the known_y's argument are 0 and the data points of the known_x's argument are 1:
Slope and Intercept(Object, Object) return a #DIV/0! error. The Slope and Intercept(Object, Object) algorithm is designed to look for one and only one answer, and in this case there can be more than one answer.
LinEst(Object, Object, Object, Object) returns a value of 0. The LinEst(Object, Object, Object, Object) algorithm is designed to return reasonable results for collinear data, and in this case at least one answer can be found.