[R] boot: how is t0 calculated?
Dear all,
I am doing log-transformed bootstrap regression using:
x=c(0.038,0.054,1.030,1.250,10.240,52.000,228.100,240.000,758.000,1502.600,0.140,9.170,280.000,1.000,0.150,0.388,20)
y=c(3961.5,25987.5,526557,321094.5,642,23592715.5,4050,
228853521.1,320980392,42900,58435.5,13525240.5,621195600,102,30567.0,296100.0,480)
xy = data.frame(x=x,y=y)
reg.ln = function(storage, indices){
storage = storage[indices,]
res.lm = lm(log(y)~log(x), data=storage)
coefficients(res.lm)
}
xy.boot = boot(xy, reg.ln, 2000)
Why does the Intercept given by xy.boot$t0 differs from
mean(co.boot$t[,1])?
How are the t0 values calculated?
Any help is appreciated!
Thanks
Thomas
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[R] calculate RMSE using bootstrap
Dear all,
I need to calculate confidence intervals of a and b and root mean square
error (RMSE) of a power law given by
Y = a X^b
I calculate the confidence intervals by:
reg.ln = function(tab.xy, indices){
tab.xy = storage[indices,]
res.lm = lm(log(y)~log(x), data=tab.xy)
coefficients(res.lm)
}
xy.boot = boot(tab.xy, reg.ln, 2000)
boot.ci(xy.boot)
where tab.xy is a dataframe containing x and y.
Is there any way to calculate the mean RMSE of the 2000 fitted models,
e.g. identify the data which are not used in the random sub-sample
generated by boot() and calculate the RMSE of the fitted models.
Kind regards for any help
Thomas
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[R] fitting power growth
Dear all I am using the x and y vectors as defined below and want do to a power law regression: y = a x^b using > lm(log(y)~log(x)) gives reasonable values (b=1.23) but is not very popular due to biases of back-transformation from log to non-log values. Using > nls(y~a*x^b,start=list(a=100,b=1.23)) is statistically more correct but gives a too large "a" value and a too small "b" value. Doe anybody have a better way to solve the above power-law regression (using for instance maximum likely hood or anything else). Kind regards for your help Thomas > x [1] 744.90 806.40 838.00 910.70 1818.60 2870.10 4070.00 4476.80 4857.60 4858.10 [11] 5916.40 13970.80 27306.60 28226.60 2532.10 2658.40 18863.10 758.0054.0079.00 [21] 139.0046.70 1003.0024.00 106.00 186.00 1503.00 228.0010.24 162.00 [31] 381.70 312.60 209.00 246.00 221.20 1151.55 > y [1] 1.500e+08 2.850e+08 1.800e+08 1.800e+08 6.300e+08 7.200e+08 1.170e+09 1.095e+09 1.620e+09 [10] 4.650e+09 1.575e+09 4.200e+09 7.755e+09 8.745e+09 9.900e+08 6.600e+08 1.077e+10 3.450e+08 [19] 1.350e+07 2.550e+07 6.600e+07 6.000e+06 3.300e+07 1.500e+06 4.500e+06 7.500e+06 2.415e+08 [28] 6.900e+07 9.000e+05 9.450e+06 3.510e+07 4.880e+07 3.100e+06 1.930e+07 2.270e+07 5.270e+07 __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] help with expression
Hi all,
I still fail to plot an axis title with the following expression:
plot(0,xlab=expression('(SOC [' * kgm^{-2} * '])' * ^{-2}))
the xlab should look like: (SOC [kgm^2])^0.25
with an out bracket and a superscript.
Thanks for your advice.
Thomas
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[R] determing font type in expression
Dear R-Maillist members, I would like to label the y-axis of a plot with a mathematical expression "sed.rate mm a-1", where the "-1" is printed subscript. I am using font.lab=15 for the x-axis. However, when plotting the y-axis with the expression-function it appears in a different font. Does anybody knows how to use font.lab=15 in the expression as well? Cheers Thomas __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] creating expression with for-loop
Dear listmembers
I would like to create an expression that looks like
labl = expression(10^1,10^2,10^3,10^4,10^5)
using a for-loop. However
for (i in 1:5){ labl[i]=expression(10^i) }
does not do the right thing. Does anybody knows help?
Thanks
Thomas
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[R] filled.contour with log axis
Dear all, I would like to generate a filled.contour plot with log x and y axis, however using: filled.contour(as.line,log="xy") results in a warning message. Does anybody knos what to do? Thanks Thomas __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] axis names in triangle.plot
Thanks for this advice. grain was not a data.frame but a matrix. Now it works:-) Cheers Thomas Stéphane Dray schrieb: > Hi Thomas, > This looks quite strange. By default, the function use the column > names as labels. > What is grain ? A data.frame ? Why have you duplicated row.names? > Please return the results of class(grain) and names(grain) > > Cheers, > PS: If you have questions related to ade4, you can use the adelist > (http://listes.univ-lyon1.fr/wws/info/adelist) > > > Thomas Hoffmann wrote: >> Hi folks, >> >> I am using a data.frame with sediment grain sizes: >> >> > grain >> sand silt clay >> OAT 10.03 56.77 18.25 >> OAT 10.40 57.40 17.94 >> WG1 50.03 20.68 12.57 >> WG1 43.20 25.69 13.41 >> WG1 33.89 31.10 14.48 >> WG2 2.84 62.81 20.79 >> WG2 2.79 60.46 19.16 >> WG2 16.27 33.04 6.48 >> WG2 1.39 57.90 9.13 >> WG3 4.54 52.91 17.20 >> WG3 5.20 50.55 15.65 >> WG3 7.71 49.13 10.80 >> WG3 4.43 50.03 11.83 >> WG3 1.72 57.53 14.20 >> WG3 1.51 58.99 13.96 >> >> I would like to do a trinagle.plot with labeled axis-names "sand" >> "silt" and "clay". However using the command: >> >> tringle.plot(grain) >> >> from ade4-apckage) does not plot the axis names and there is no >> paramter to set the labels like "xlab" in the plot command. Does >> anybody has a good advice? >> >> Thanks in advance >> Thomas >> >> __ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> >> >> > > __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] axis names in triangle.plot
Hi folks, I am using a data.frame with sediment grain sizes: > grain sand silt clay OAT 10.03 56.77 18.25 OAT 10.40 57.40 17.94 WG1 50.03 20.68 12.57 WG1 43.20 25.69 13.41 WG1 33.89 31.10 14.48 WG2 2.84 62.81 20.79 WG2 2.79 60.46 19.16 WG2 16.27 33.04 6.48 WG2 1.39 57.90 9.13 WG3 4.54 52.91 17.20 WG3 5.20 50.55 15.65 WG3 7.71 49.13 10.80 WG3 4.43 50.03 11.83 WG3 1.72 57.53 14.20 WG3 1.51 58.99 13.96 I would like to do a trinagle.plot with labeled axis-names "sand" "silt" and "clay". However using the command: tringle.plot(grain) from ade4-apckage) does not plot the axis names and there is no paramter to set the labels like "xlab" in the plot command. Does anybody has a good advice? Thanks in advance Thomas __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] fit to power law with inknown zero
Dear R-helpers I would like to do a fit of the form: y = a (x+c)**b, where a, b and c are unknown. Does anybody know how to do it? Thanks Thomas __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] power law fit with unknown zero
Dear R-helpers I would like to do a fit of the form: y = a (x+c)**b, where a, b and c are unknown. Does anybody know how to do it? Thanks Thomas __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
