What is the statistical function:LOGEST in Excel?

[N I C K]

Hello folks,
First thing I would like to Thanks all of you. You really helped me a lot last time. I am now having a doubt and hope that I will get the same help.!! This time I have stuck in statistical functions that are used in Excel. I am not getting the function Logest properly. So expecting some help from your side.!! Please tell me what is the statistical function:LOGEST in Excel? Try to reply me as early as possible.!!

[super soaker]

LOGEST is evaluated by calling the function for the LINEST. Major changes to LINEST for Excel 2003 and later versions of Excel are summarized and their implications for LOGEST are noted. The statistical functions in Microsoft Excel 2004 for Macintosh were updated using the same algorithms Excel 2003 and later versions of Excel. LOGEST performance has been improved because LINEST has been greatly improved in Excel 2003 and in later versions of Excel. If you are using an earlier version of Excel, check that predictor columns are not collinear before using LOGEST.

[Sam.D]

The LOGEST (known_y's, known_x's, constant statistics) function is used to perform regression in which an exponential curve is adjusted. A test result of least squares is used and LOGEST trying to find the best fit under that criterion. Data represent known_y 's on the dependent variable and known_x represent data on one or more independent variables. The second argument is optional. If omitted, it is supposed to be an array of the same size as known_y 's containing the values (1, 2, 3 ,...).

[kattman]

Assuming there exists p predictor variables, LOGEST fits an equation of the form given below :

• y = b * (m1^x1) * (m2^x2) * … * (mp^xp)

values of coefficients, b, m1, m2 ,..., mp give the best fit to the data. If the third argument "constant" is set to TRUE, you want the regression model to include the constant b in the equation in its previous model. If it is set to FALSE, the multiplicative constant b is excluded from the regression model by forcing equal to one. The third argument is optional. If omitted, it is interpreted as the value is TRUE.

[DANIEL 602]

I would also like to explain you about the equation in which LOGEST fits. The last argument LOGEST is set to TRUE if you want additional statistics, including various sum of squares, r squared, f and statistical standard errors of regression coefficients. In this case, LOGEST is normally required as an array formula. The last argument is optional. If omitted, it is interpreted as FALSE. The dimensions of the table are five lines by a number of columns equal to the number of independent variables plus one if the third argument is set to TRUE (over 0) if the third argument is set to TRUE.

[kattman]

The following is the Syntax of the Logest :

• LOGEST(known_y's, known_x's, constant, statistics)

The last three arguments are all optional LOGEST. If you omit the second argument, LOGEST involves a single predictor that contains the entries (1, 2, 3 ,...}. If you omit the third argument, it is interpreted as the value is TRUE. If you omit the fourth argument, it is interpreted as FALSE. If known_y occupies one column by m rows, the known_x must be c columns by m rows where c is greater than or equal to one. C is the number of predictor variables, m is the number of data points. Similar relationships should hold if known_y 's is placed on one line, in which case the known_x must be in line r. (R must be greater than or equal to 1.) Constant and statistics are logical arguments that must be set to TRUE or FALSE. In Excel, the arguments must be set to 0 or 1 and are interpreted by Excel as FALSE or TRUE, respectively.