| | | This function can return an array |
| | | 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, 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" = True, then, b is calculated normally. |
| | | If "const" = False, then b is set equal to 0 (zero), and the m-values are adjusted so that y = mx. |
| | | If "const" is left blank, then True is used. |
| | | 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. |
| | | Suppose a business wants to purchase a tract of land in July, the start of the next fiscal year. The business collects cost information that covers the most recent 12 months for a typical tract in the desired area. Known_y values are in cells B2:B13; the known_y values are $133,890, $135,000, $135,790, $137,300, $138,130, $139,100, $139,900, $141,120, $141,890, $143,230, $144,000, $145,290. |
| | | The company can expect a typical tract of land to cost about $150,244 if it waits until July. The preceding formula uses the default array {1;2;3;4;5;6;7;8;9;10;11;12} for the known_x's argument, corresponding to the 12 months of sales data. The array {13;14;15;16;17} corresponds to the next five months. |
