Dear R-usrs,
I am trying to perform a MANOVA on a data frame with 31 columns about soil
parameters and 1 column containing the explanatory variable (Fraction) that
have three levels.
my code is the following:
datam <- read.table("data_manova2.csv", header=T,
sep=",")
names(datam)
manova_fraction2 <- manova(cbind(pH, AWC, WEOC, WEN, C.mic, CO2.C, Ca, Mg,
K, Na, sol.exch.Fe, easily.reducible.Fe, amourphou.Fe.oxide...Fe.OM,
crystalline.Fe.oxides, TN, TOC, NH4.N, NO3.N, N.org, organic.P, avaiable.P,
Total.PLFA, Tot.Bat, Gram., Gram..1, Funghi, AMF, protozoa, actinomiceti,
non.specifici) ~ as.factor(Fraction), data= datam)
summary(manova_fraction2)
when I did the summary I got this error
> summary(manova_fraction2)
Error in summary.manova(manova_fraction2) : residuals have rank 18 < 30
?Is this error possibly due to high correlation between my variables?
Many thanks in advance,
--
Gian
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> On 30 Mar 2015, at 17:11 , Gian Maria Niccol? Benucci <gian.benucci at gmail.com> wrote: > > Dear R-usrs, > > I am trying to perform a MANOVA on a data frame with 31 columns about soil > parameters and 1 column containing the explanatory variable (Fraction) that > have three levels. > my code is the following: > > datam <- read.table("data_manova2.csv", header=T, sep=",") > names(datam) > > manova_fraction2 <- manova(cbind(pH, AWC, WEOC, WEN, C.mic, CO2.C, Ca, Mg, > K, Na, sol.exch.Fe, easily.reducible.Fe, amourphou.Fe.oxide...Fe.OM, > crystalline.Fe.oxides, TN, TOC, NH4.N, NO3.N, N.org, organic.P, avaiable.P, > Total.PLFA, Tot.Bat, Gram., Gram..1, Funghi, AMF, protozoa, actinomiceti, > non.specifici) ~ as.factor(Fraction), data= datam) > > summary(manova_fraction2) > > when I did the summary I got this error > >> summary(manova_fraction2) > Error in summary.manova(manova_fraction2) : residuals have rank 18 < 30 > > ?Is this error possibly due to high correlation between my variables? >Nope. Too few observations. For classical MANOVA, you need > p degrees of freedom to determine the covariance matrix with full rank. As far as I can tell, you have only 21 observations (21-3=18 degrees of freedom) for your p=30 response variables.> Many thanks in advance,-- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
Hi Peter, Thank you so much for your tips. Have a nice Easter. Gian Il gioved? 2 aprile 2015, peter dalgaard <pdalgd at gmail.com> ha scritto:> > > On 30 Mar 2015, at 17:11 , Gian Maria Niccol? Benucci < > gian.benucci at gmail.com <javascript:;>> wrote: > > > > Dear R-usrs, > > > > I am trying to perform a MANOVA on a data frame with 31 columns about > soil > > parameters and 1 column containing the explanatory variable (Fraction) > that > > have three levels. > > my code is the following: > > > > datam <- read.table("data_manova2.csv", header=T, sep=",") > > names(datam) > > > > manova_fraction2 <- manova(cbind(pH, AWC, WEOC, WEN, C.mic, CO2.C, Ca, > Mg, > > K, Na, sol.exch.Fe, easily.reducible.Fe, amourphou.Fe.oxide...Fe.OM, > > crystalline.Fe.oxides, TN, TOC, NH4.N, NO3.N, N.org, organic.P, > avaiable.P, > > Total.PLFA, Tot.Bat, Gram., Gram..1, Funghi, AMF, protozoa, actinomiceti, > > non.specifici) ~ as.factor(Fraction), data= datam) > > > > summary(manova_fraction2) > > > > when I did the summary I got this error > > > >> summary(manova_fraction2) > > Error in summary.manova(manova_fraction2) : residuals have rank 18 < 30 > > > > ?Is this error possibly due to high correlation between my variables? > > > > Nope. Too few observations. For classical MANOVA, you need > p degrees of > freedom to determine the covariance matrix with full rank. As far as I can > tell, you have only 21 observations (21-3=18 degrees of freedom) for your > p=30 response variables. > > > Many thanks in advance, > > -- > Peter Dalgaard, Professor, > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Email: pd.mes at cbs.dk <javascript:;> Priv: PDalgd at gmail.com <javascript:;> > > > > > > > > >-- Gian Maria Niccol? Benucci, PhD University of Perugia Dept. of Agricultural, Food and Environmental Sciences Borgo XX Giugno, 74 06121 - Perugia, ITALY Tel: +390755856417 Email: gian.benucci at gmail.com *----- Do not print this email unless you really need to. Save paper and protect the environment! -----* [[alternative HTML version deleted]]