Hi-

I'm wrestling with some of my data apparently not being called into a GLM or
an LM.  I'm looking at factors affecting fish annual catch rates (ie. CPUE)
over 30 years.  Two of the factors I'm using are sea surface temperature and
sea surface temperature anomaly.  A small sample of my data is below:

 


CPUE

Year

Vessel_ID

Base_Port

Boat_Lgth

Planing

SST

Anomaly


0.127

1976

2

BOI

40

Planing

19.4

-0.308


0.059

1976

30

BOI

40

Displacement

19.4

-0.308


0.033333

1977

46

BOI

45

Displacement

18.5

-1.008


0.169231

1977

2

BOI

40

Planing

18.5

-1.008


0.044118

1977

19

BOI

34

Planing

18.5

-1.008


0.114286

1977

29

WHANGAROA

42

Displacement

18.5

-1.008

 

Have defined Year, Vessel_ID, Base_Port, Boat_Lgth, Planing as factors, and
CPUE, SST, Anomaly are continuous variables. 

 

The formula I'm calling is: glm(formula = log(CPUE) ~ Year + Vessel_ID +
SST, data = marlin).  A summary of the glm includes the following output:

 

Coefficients: (1 not defined because of singularities)

            Estimate Std. Error t value Pr(>|t|)

Vessel_ID80 -0.54093    0.23380  -2.314 0.021373 *  

Vessel_ID83 -0.36499    0.20844  -1.751 0.080977 .  

Vessel_ID84 -0.23386    0.19098  -1.225 0.221718    

SST               NA         NA      NA       NA    

 

Can someone explain the output "Coefficients: (1 not defined because of
singularities)"? What does this mean?  I'm guessing that something to do
with my SST data is causing a "singularity" but I don't know where to go
from there?  Have inspected various R discussions on this, but I haven't
found the information I need.  

 

Many thanks,

 

Tim Sippel (MSc)

School of Biological Sciences

Auckland University

Private Bag 92019

Auckland 1020

New Zealand

+64-9-373-7599 ext. 84589 (work)

+64-9-373-7668 (Fax)

+64-21-593-001 (mobile)

 


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