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help for ^bevholt^                                                [STB-53: sg128]
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Beverton-Holt method for von Bertalanffy growth function parameter estimation
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     ^bevholt^  msizevar agevar [^if^ exp] [^in^ range], ^l^inf^(^#^)^ 
     [ ^g^en^(^estsizevar^)^ ^nog^raph graph_options ]


Description
-----------

This program estimates K and t_0 (for a given L_inf) parameters of the 
von Bertalanffy growth function using mean size (length) at age data 
according to the procedure proposed by Beverton and Holt (1957). This ado 
file draws the ln(L_inf - l_t) - age graph and provides a table with the
estimated K and t_0 parameters in addition to the estimated von 
Bertalanffy growth function.


Options
-------

^linf(^#^)^ is not optional. It has to be entered in order to run the program.
	The Linfinite value can be retrieved from the ^fordwal^ or ^gullplot^
	routines.

^gen(^estsizevar^)^ permits to create a variable containing the estimated sizes
	with the growth function determined.

^nograph^ suppresses the graph drawing.

graph_options are any of the options allowed with ^graph, twoway^.


Remarks
-------

If the delta_t-age points do not have a slope less than zero, the program
halts and exits with an error message.


Examples
--------

	. ^bevholt mlength age, linf(63.1687)^

Will display the Beverton-Holt plot, a table with regression info, the values 
for K and t_0 parameters and the final estimation of the von Bertalanffy 
growth function.

	. ^bevholt mlength age, linf(63.1687) xlab ylab^

Nice numbers for the axis added.

	. ^bevholt mlength age, linf(63.1687) nog gen(estml)^

Suppresses the graphical display leaving only the table with numerical 
results and generates a new variable (estml) containing the estimated
sizes by using the von Bertalanffy growth function determined.


Author
------

Isaias H. Salgado-Ugarte
Universidad Nacional Autonoma de Mexico
Facultad de Estudios Superiores Zaragoza
Biologia, Guelatao 66 Col. Ejercito de Oriente
Iztapalapa 09230, Mexico D.F., Mexico
(Fax 52-5-773-0151)
e-mail: isalgado@@servidor.unam.mx


Also see
--------

    STB: snp6 (STB-16); sg23 (STB-18) snp6.1 (STB-26); snp6.2 (STB-27)
         snp13 (STB-38)

On-line: ^help^ for @fordwal@, @gullplot@, @gullholt@, @nlvbgf@