AFAICS this has essentially nothing to do with R. Please post elsewhere,
e.g. on a statistics list like stats.stackexchange.com.
Cheers,
Bert
On Fri, May 29, 2015 at 6:44 AM, Abolfazl Saghafi <
abolfazl.sagh...@gmail.com> wrote:
> Can some help me with a question on this bass model, please
>
>
Can some help me with a question on this bass model, please
As I read some articles on this topic, I understand that
1. the bass formula is
N(t) = pm + (q-p) N(t-1) - (q/m) (N(t-1))^2
2. which is a difference equation with the solution
N(t) = m (1 − exp(−(p+q)t)) / (1 + (q/p)exp(−(p+q)t))
3. So, u
I'm trying to fit the Bass Diffusion Model using the nls function in R but
I'm running into a strange problem. The model has either two or three
parameters, depending on how it's parameterized, p (coefficient of
innovation), q (coefficient of immitation), and sometimes m (maximum market
share).
T)
From: Yifen
To: r-help@r-project.org
Subject: Re: [R] Problems with nls
Message-ID: <1354029073140-4650971.p...@n4.nabble.com>
Content-Type: text/plain; charset=us-ascii
Hi all,
I am encountering the same problem when I use nls to estimate the Bass
diffusion model. I used similar cod
Hi all,
I am encountering the same problem when I use nls to estimate the Bass
diffusion model. I used similar code in the previous replies and it works
with the data in this original post. However, I got an error when I use my
own data.
Error in nls(formula = Bass.Model, start = c(p = 0.03, q =
Those are in fact the coefficients for p and q they are estimating, though
their M is different. Who knows what they did with that.
The data source was:
Title: Diffusion models of mobile telephony in Greece
Source: Telecommunications policy [0308-5961] Michalakelis yr:2008 vol:32
iss:3-4 pg:234
On Wed, Jun 15, 2011 at 6:05 PM, Daniel Malter wrote:
> There may be two issues here. The first might be that, if I understand the
> Bass model correctly, the formula you are trying to estimate is the adoption
> in a given time period. What you supply as data, however, is the cumulative
> adoption
There may be two issues here. The first might be that, if I understand the
Bass model correctly, the formula you are trying to estimate is the adoption
in a given time period. What you supply as data, however, is the cumulative
adoption by that time period.
The second issue might be that the linea
On Wed, Jun 15, 2011 at 5:35 PM, Gabor Grothendieck
wrote:
> On Wed, Jun 15, 2011 at 11:06 AM, Christopher Hulme-Lowe
> wrote:
>> I'm trying to fit the Bass Diffusion Model using the nls function in R but
>> I'm running into a strange problem. The model has either two or three
>> parameters, depe
On Wed, Jun 15, 2011 at 11:06 AM, Christopher Hulme-Lowe
wrote:
> I'm trying to fit the Bass Diffusion Model using the nls function in R but
> I'm running into a strange problem. The model has either two or three
> parameters, depending on how it's parameterized, p (coefficient of
> innovation), q
I'm trying to fit the Bass Diffusion Model using the nls function in R but
I'm running into a strange problem. The model has either two or three
parameters, depending on how it's parameterized, p (coefficient of
innovation), q (coefficient of immitation), and sometimes m (maximum market
share). Reg
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