Hallo
yes I tried it as well and it works;

Thank you a lot

Maria

________________________________
From: Dennis Murphy [djmu...@gmail.com]
Sent: 15 March 2011 21:36
To: Lathouri, Maria
Cc: r-help@r-project.org
Subject: Re: [R] fitting a distribution to a ecdf plot

Hi:

The fitdistrplus package from CRAN may be useful. I tried it on your data and 
the lognormal seemed to fit well, apart from the outlier. I just followed the 
vignette that accompanies the package.

library(fitdistplus)

plotdist(NOEccu)                             # ecdf
descdist(NOEccu, boot = 1000)      # Cullen-Frey graph based on 1000 bootstrap 
samples

# The Cullen-Frey graph suggests that the distribution is somewhere between a 
Gamma and lognormal

# Weibull
N1w <- fitdist(NOEccu, 'weibull')
# Warning messages:
# 1: In dweibull(x, shape, scale, log) : NaNs produced
# 2: In dweibull(x, shape, scale, log) : NaNs produced
plot(N1w)
summary(N1w)

# Gamma
N1g <- fitdist(NOEccu, 'gamma')
# Warning messages:
# 1: In dgamma(x, shape, scale, log) : NaNs produced
# 2: In dgamma(x, shape, scale, log) : NaNs produced
# 3: In dgamma(x, shape, scale, log) : NaNs produced
# 4: In dgamma(x, shape, scale, log) : NaNs produced
plot(N1g)
summary(N1g)

# Lognormal
N1l <- fitdist(NOEccu, 'lnorm')
plot(N1l)
summary(N1l)

Try it out and see if it suits your needs.

HTH,
Dennis

On Tue, Mar 15, 2011 at 9:00 AM, Lathouri, Maria 
<m.lathour...@imperial.ac.uk<mailto:m.lathour...@imperial.ac.uk>> wrote:
Dear all,

I need to plot an cumulative distribution plot of a variable and then to fit a 
distribution to that, probably a weibull or lognormal.

I have plotted the ecdf as
> plot(ecdf(x))

but I haven't managed to fit the distribution. I have as well attached the data.

I would appreciate if you could help me on that.

Thank you.

Kind regards
Maria

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