Hi
I am new to the list. I am a PhD student and am looking for some help. I
have analysed the data from a study I conducted by using non-linear
regressions with the equation: (y= a - be-cx). I write it like this when I write
it up but when I used it in SPSS I used (y= a + becx) but constrained a to be
positive and b and c to be negative. I am unsure how to reference this
equation. SPSS states
The asymptotic regression model has form y=b1+b2eb3x. When b1>0,
b2<0, and b3<0, it gives Mistcherlich's model of the "law of diminishing
returns". Although in another area of the help file it refers to Metcherlich Law
of Diminishing Returns: b1 + b2 * exp(-b3 * x).
Has anyone else used this equation and does anyone know how I should
reference it, or know of a paper I could use as a reference?
Any suggestions would be a big help.
Many thanks, Pippa
Phillippa Lally
Research Psychologist
Cancer Research UK Health Behaviour Unit
Department of Epidemiology and Public Health
University College London
2nd Floor Brook House
2-16 Torrington Place
London
WC1E 6BT
Tel: 02076 796644
Fax: 02078 132848
Email: [log in to unmask]
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