Hi,
Can someone please tell me what such an error message
could mean. i.e where a problem must have arised.
Error in uniroot(function(n) eval(p.body) - power,
c(2, 1e+07)) :
f() values at end points not of opposite sign
Thank you
cilver
=====
=====================
Sylvie B. Forkusam
Eppelheimer Str.52/A2-5-2
69115 Heidelberg, Germany
Tel: (0049)-06221/346913
Mobile: 0179-6816276
error message
4 messages · forkusam, Peter Dalgaard, Uwe Ligges
forkusam <forkusam at yahoo.com> writes:
Hi,
Can someone please tell me what such an error message
could mean. i.e where a problem must have arised.
Error in uniroot(function(n) eval(p.body) - power,
c(2, 1e+07)) :
f() values at end points not of opposite sign
Looks like the innards of one of the power calculations, finding n to achieve a given power. You'd likely get an error like that if the power is not between 0 and 1, but how about telling us what you were trying to do?
O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
2 days later
I am trying to calculate n, using power.t.test
power.t.test(n=NULL,delta=delta, sd=sigmaEins,
sig.level= alpha, power=power, type=c("two.sample"),
alternative=c("two.sided"))
The values of the parameter are read in from a file.
I have no idea what the error message means.
--- Peter Dalgaard <p.dalgaard at biostat.ku.dk> wrote:
forkusam <forkusam at yahoo.com> writes:
Hi, Can someone please tell me what such an error
message
could mean. i.e where a problem must have arised.
Error in uniroot(function(n) eval(p.body) - power,
c(2, 1e+07)) :
f() values at end points not of opposite
sign Looks like the innards of one of the power calculations, finding n to achieve a given power. You'd likely get an error like that if the power is not between 0 and 1, but how about telling us what you were trying to do? -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
===== ===================== Sylvie B. Forkusam Eppelheimer Str.52/A2-5-2 69115 Heidelberg, Germany Tel: (0049)-06221/346913 Mobile: 0179-6816276
On Sat, 24 Jan 2004, forkusam wrote:
I am trying to calculate n, using power.t.test
power.t.test(n=NULL,delta=delta, sd=sigmaEins,
sig.level= alpha, power=power, type=c("two.sample"),
alternative=c("two.sided"))
The values of the parameter are read in from a file.
I have no idea what the error message means.
Peter Dalgaard asked you to specify a *reproducible* example. So, please specify some values for delta, sigmaEins, alpha, power. Uwe Ligges
--- Peter Dalgaard <p.dalgaard at biostat.ku.dk> wrote:
forkusam <forkusam at yahoo.com> writes:
Hi, Can someone please tell me what such an error
message
could mean. i.e where a problem must have arised.
Error in uniroot(function(n) eval(p.body) - power,
c(2, 1e+07)) :
f() values at end points not of opposite
sign Looks like the innards of one of the power calculations, finding n to achieve a given power. You'd likely get an error like that if the power is not between 0 and 1, but how about telling us what you were trying to do? -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
===== ===================== Sylvie B. Forkusam Eppelheimer Str.52/A2-5-2 69115 Heidelberg, Germany Tel: (0049)-06221/346913 Mobile: 0179-6816276
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