Title: | Generating Multi-State Survival Data |
---|---|
Description: | Generation of survival data with one (binary) time-dependent covariate. Generation of survival data arising from a progressive illness-death model. |
Authors: | Artur Araujo [aut, cre] |
Maintainer: | Artur Araujo <[email protected]> |
License: | GPL-3 |
Version: | 1.0.5 |
Built: | 2025-03-01 06:07:02 UTC |
Source: | https://github.com/arturstat/gensurv |
The genSurv software permits to generate data with one binary time-dependent covariate and data stemming from a progressive illness-death model.
Package: | genSurv |
Type: | Package |
Version: | 1.0.5 |
Date: | 2021-11-11 |
License: | GPL-3 |
LazyLoad: | yes |
Artur Araújo, Luís Meira-Machado [email protected]
and Susana Faria [email protected]
Maintainer: Artur Araújo [email protected]
Anderson, P.K., Gill, R.D. (1982). Cox's regression model for counting processes: a large sample study. Annals of Statistics, 10(4), 1100-1120. doi:10.1214/aos/1176345976
Cox, D.R. (1972). Regression models and life tables. Journal of the Royal Statistical Society: Series B, 34(2), 187-202. doi:10.1111/j.2517-6161.1972.tb00899.x
Jackson, C. (2011). Multi-State Models for Panel Data: The msm Package for R. Journal of Statistical Software, 38(8), 1–28. doi:10.18637/jss.v038.i08
Johnson, M. E. (1987). Multivariate Statistical Simulation, John Wiley and Sons.
Johnson, N., Kotz, S. (1972). Distribution in statistics: continuous multivariate distributions, John Wiley and Sons.
Lu J., Bhattacharya G. (1990). Some new constructions of bivariate weibull models. Annals of Institute of Statistical Mathematics, 42(3), 543-559. doi:10.1007/BF00049307
Meira-Machado, L., Cadarso-Suárez, C., De Uña- Álvarez, J., Andersen, P.K. (2009). Multi-state models for the analysis of time to event data. Statistical Methods in Medical Research, 18(2), 195-222. doi:10.1177/0962280208092301
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Roca-Pardiñas, J. (2011). p3state.msm: Analyzing Survival Data from an Illness-Death Model. Journal of Statistical Software, 38(3), 1-18. doi:10.18637/jss.v038.i03
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
Therneau, T.M., Grambsch, P.M. (2000). Modelling survival data: Extending the Cox Model, New York: Springer.
CMM
Function to coerce objects of class TDCM
and THMM
to objects of class CMM
.
as.CMM(x) is.CMM(x)
as.CMM(x) is.CMM(x)
x |
Any R object. |
An object with two classes one being data.frame
and the other CMM
.
Artur Araújo, Luís Meira Machado and Susana Faria
Cox, D.R. (1972). Regression models and life tables. Journal of the Royal Statistical Society: Series B, 34(2), 187-202. doi:10.1111/j.2517-6161.1972.tb00899.x
Jackson, C. (2011). Multi-State Models for Panel Data: The msm Package for R. Journal of Statistical Software, 38(8), 1–28. doi:10.18637/jss.v038.i08
Meira-Machado, L., Cadarso-Suárez, C., De Uña- Álvarez, J., Andersen, P.K. (2009). Multi-state models for the analysis of time to event data. Statistical Methods in Medical Research, 18(2), 195-222.
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Roca-Pardiñas, J. (2011). p3state.msm: Analyzing Survival Data from an Illness-Death Model. Journal of Statistical Software, 38(3), 1-18. doi:10.18637/jss.v038.i03
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
Therneau, T.M., Grambsch, P.M. (2000). Modelling survival data: Extending the Cox Model, New York: Springer.
as.TDCM
,
as.THMM
,
genCMM
,
genTDCM
,
genTHMM
.
# generate TDCM data tdcmdata <- genTDCM(n=100, dist="exponential", corr=0, dist.par=c(1,1), model.cens="uniform", cens.par=1, beta=c(-3,2), lambda=10) # coerce TDCM data to CMM data cmmdata0 <- as.CMM(tdcmdata) head(cmmdata0, n=20L) # generate THMM data thmmdata <- genTHMM( n=100, model.cens="uniform", cens.par=80, beta= c(0.09,0.08,-0.09), covar=80, rate= c(0.05,0.04,0.05) ) # coerce THMM data to CMM data cmmdata1 <- as.CMM(thmmdata) head(cmmdata1, n=20L)
# generate TDCM data tdcmdata <- genTDCM(n=100, dist="exponential", corr=0, dist.par=c(1,1), model.cens="uniform", cens.par=1, beta=c(-3,2), lambda=10) # coerce TDCM data to CMM data cmmdata0 <- as.CMM(tdcmdata) head(cmmdata0, n=20L) # generate THMM data thmmdata <- genTHMM( n=100, model.cens="uniform", cens.par=80, beta= c(0.09,0.08,-0.09), covar=80, rate= c(0.05,0.04,0.05) ) # coerce THMM data to CMM data cmmdata1 <- as.CMM(thmmdata) head(cmmdata1, n=20L)
TDCM
Function to coerce objects of class CMM
and THMM
to objects of class TDCM
.
as.TDCM(x) is.TDCM(x)
as.TDCM(x) is.TDCM(x)
x |
Any R object. |
An object with two classes one being data.frame
and the other TDCM
.
Artur Araújo, Luís Meira Machado and Susana Faria
Cox, D.R. (1972). Regression models and life tables. Journal of the Royal Statistical Society: Series B, 34(2), 187-202. doi:10.1111/j.2517-6161.1972.tb00899.x
Jackson, C. (2011). Multi-State Models for Panel Data: The msm Package for R. Journal of Statistical Software, 38(8), 1–28. doi:10.18637/jss.v038.i08
Meira-Machado, L., Cadarso-Suárez, C., De Uña- Álvarez, J., Andersen, P.K. (2009). Multi-state models for the analysis of time to event data. Statistical Methods in Medical Research, 18(2), 195-222. doi:10.1177/0962280208092301
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Roca-Pardiñas, J. (2011). p3state.msm: Analyzing Survival Data from an Illness-Death Model. Journal of Statistical Software, 38(3), 1-18. doi:10.18637/jss.v038.i03
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
Therneau, T.M., Grambsch, P.M. (2000). Modelling survival data: Extending the Cox Model, New York: Springer.
as.CMM
,
as.THMM
,
genCMM
,
genTDCM
,
genTHMM
.
# generate CMM data cmmdata <- genCMM( n=1000, model.cens="uniform", cens.par=2.5, beta=c(2,1,-1), covar=10, rate=c(1,5,1,5,1,5) ) # coerce CMM data to TDCM data tdcmdata0 <- as.TDCM(cmmdata) head(tdcmdata0, n=20L) # generate THMM data thmmdata <- genTHMM( n=100, model.cens="uniform", cens.par=80, beta= c(0.09,0.08,-0.09), covar=80, rate= c(0.05,0.04,0.05) ) # coerce THMM data to TDCM data tdcmdata1 <- as.TDCM(thmmdata) head(tdcmdata1, n=20L)
# generate CMM data cmmdata <- genCMM( n=1000, model.cens="uniform", cens.par=2.5, beta=c(2,1,-1), covar=10, rate=c(1,5,1,5,1,5) ) # coerce CMM data to TDCM data tdcmdata0 <- as.TDCM(cmmdata) head(tdcmdata0, n=20L) # generate THMM data thmmdata <- genTHMM( n=100, model.cens="uniform", cens.par=80, beta= c(0.09,0.08,-0.09), covar=80, rate= c(0.05,0.04,0.05) ) # coerce THMM data to TDCM data tdcmdata1 <- as.TDCM(thmmdata) head(tdcmdata1, n=20L)
THMM
Function to coerce objects of class CMM
and TDCM
to objects of class THMM
.
as.THMM(x) is.THMM(x)
as.THMM(x) is.THMM(x)
x |
Any R object. |
An object with two classes one being data.frame
and the other THMM
.
Artur Araújo, Luís Meira Machado and Susana Faria
Cox, D.R. (1972). Regression models and life tables. Journal of the Royal Statistical Society: Series B, 34(2), 187-202. doi:10.1111/j.2517-6161.1972.tb00899.x
Jackson, C. (2011). Multi-State Models for Panel Data: The msm Package for R. Journal of Statistical Software, 38(8), 1–28. doi:10.18637/jss.v038.i08
Meira-Machado, L., Cadarso-Suárez, C., De Uña- Álvarez, J., Andersen, P.K. (2009). Multi-state models for the analysis of time to event data. Statistical Methods in Medical Research, 18(2), 195-222. doi:10.1177/0962280208092301
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Roca-Pardiñas, J. (2011). p3state.msm: Analyzing Survival Data from an Illness-Death Model. Journal of Statistical Software, 38(3), 1-18. doi:10.18637/jss.v038.i03
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
Therneau, T.M., Grambsch, P.M. (2000). Modelling survival data: Extending the Cox Model, New York: Springer.
as.CMM
,
as.TDCM
,
genCMM
,
genTDCM
,
genTHMM
.
# generate CMM data cmmdata <- genCMM( n=1000, model.cens="uniform", cens.par=2.5, beta=c(2,1,-1), covar=10, rate=c(1,5,1,5,1,5) ) # coerce CMM data to THMM data thmmdata0 <- as.THMM(cmmdata) head(thmmdata0, n=20L) # generate TDCM data tdcmdata <- genTDCM(n=100, dist="exponential", corr=0, dist.par=c(1,1), model.cens="uniform", cens.par=1, beta=c(-3,2), lambda=10) # coerce TDCM data to THMM data thmmdata1 <- as.THMM(tdcmdata) head(thmmdata1, n=20L)
# generate CMM data cmmdata <- genCMM( n=1000, model.cens="uniform", cens.par=2.5, beta=c(2,1,-1), covar=10, rate=c(1,5,1,5,1,5) ) # coerce CMM data to THMM data thmmdata0 <- as.THMM(cmmdata) head(thmmdata0, n=20L) # generate TDCM data tdcmdata <- genTDCM(n=100, dist="exponential", corr=0, dist.par=c(1,1), model.cens="uniform", cens.par=1, beta=c(-3,2), lambda=10) # coerce TDCM data to THMM data thmmdata1 <- as.THMM(tdcmdata) head(thmmdata1, n=20L)
Generation of Cox Markov data from an illness-death model.
genCMM(n, model.cens, cens.par, beta, covar, rate)
genCMM(n, model.cens, cens.par, beta, covar, rate)
n |
Sample size. |
model.cens |
Model for censorship. Possible values are "uniform" and "exponential". |
cens.par |
Parameter for the censorship distribution. Must be greater than 0. |
beta |
Vector of three regression parameters for the three transitions: (beta_12,beta_13,beta_23). |
covar |
Parameter for generating the time-fixed covariate. An uniform distribution is used. |
rate |
Vector of dimension six: (shape1, scale1, shape2, scale2, shape3, scale3). A Weibull baseline hazard function is assumed (with two parameters) for each transition (see details below). |
The Weibull distribution with shape parameter and scale parameter
has hazard function given by:
An object with two classes, data.frame
and CMM
.
The data structure used for generating survival data from the Cox Markov Model (CMM) is similar as for the time-dependent Cox model (TDCM).
In this case the data structure has one more variable representing the transition (variable trans
).
trans=1
denotes the transition from State 1 to State 3 (without observing the intermediate event; State 2);
trans=2
denotes the transition from State 1 to State 2; and trans=3
denotes the transition from State 2 to State 3 (absorbing).
Artur Araújo, Luís Meira Machado and Susana Faria
Meira-Machado, L., Cadarso-Suárez, C., De Uña- Álvarez, J., Andersen, P.K. (2009). Multi-state models for the analysis of time to event data. Statistical Methods in Medical Research, 18(2), 195-222. doi:10.1177/0962280208092301
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Roca-Pardiñas, J. (2011). p3state.msm: Analyzing Survival Data from an Illness-Death Model. Journal of Statistical Software, 38(3), 1-18. doi:10.18637/jss.v038.i03
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
Therneau, T.M., Grambsch, P.M. (2000). Modelling survival data: Extending the Cox Model, New York: Springer.
cmmdata <- genCMM( n=1000, model.cens="uniform", cens.par=2.5, beta=c(2,1,-1), covar=10, rate=c(1,5,1,5,1,5) ) head(cmmdata, n=20L) library(survival) fit_13<-coxph(Surv(start,stop,event)~covariate, data=cmmdata, subset=c(trans==1)) fit_13 fit_12<-coxph(Surv(start,stop,event)~covariate, data=cmmdata, subset=c(trans==2)) fit_12 fit_23<-coxph(Surv(start,stop,event)~covariate, data=cmmdata, subset=c(trans==3)) fit_23
cmmdata <- genCMM( n=1000, model.cens="uniform", cens.par=2.5, beta=c(2,1,-1), covar=10, rate=c(1,5,1,5,1,5) ) head(cmmdata, n=20L) library(survival) fit_13<-coxph(Surv(start,stop,event)~covariate, data=cmmdata, subset=c(trans==1)) fit_13 fit_12<-coxph(Surv(start,stop,event)~covariate, data=cmmdata, subset=c(trans==2)) fit_12 fit_23<-coxph(Surv(start,stop,event)~covariate, data=cmmdata, subset=c(trans==3)) fit_23
Generation of survival data from a Cox Proportional Hazard Model.
genCPHM(n, model.cens, cens.par, beta, covar)
genCPHM(n, model.cens, cens.par, beta, covar)
n |
Sample size. |
model.cens |
Model for censorship. Possible values are "uniform" and "exponential". |
cens.par |
Parameter for the censorship distribution. Must be greater than 0. |
beta |
Regression parameter for the time-fixed covariate. |
covar |
Parameter for generating the time-fixed covariate. An uniform distribution is used. |
An object with two classes, data.frame
and CPHM
.
Artur Araújo, Luís Meira Machado and Susana Faria
Cox, D.R. (1972). Regression models and life tables. Journal of the Royal Statistical Society: Series B, 34(2), 187-202. doi:10.1111/j.2517-6161.1972.tb00899.x
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
cphmdata <- genCPHM(n=1000, model.cens="exponential", cens.par=2, beta= 2, covar=1) head(cphmdata, n=20L) library(survival) fit<-coxph(Surv(time,status)~covariate,data=cphmdata) summary(fit)
cphmdata <- genCPHM(n=1000, model.cens="exponential", cens.par=2, beta= 2, covar=1) head(cphmdata, n=20L) library(survival) fit<-coxph(Surv(time,status)~covariate,data=cphmdata) summary(fit)
Generating data from a Cox model with time-dependent covariates.
genTDCM(n, dist, corr, dist.par, model.cens, cens.par, beta, lambda)
genTDCM(n, dist, corr, dist.par, model.cens, cens.par, beta, lambda)
n |
Sample size. |
dist |
Bivariate distribution assumed for generating the two covariates (time-fixed and time-dependent). Possible bivariate distributions are "exponential" and "weibull" (see details below). |
corr |
Correlation parameter. Possible values for the bivariate exponential distribution are between -1 and 1 (0 for independency). Any value between 0 (not included) and 1 (1 for independency) is accepted for the bivariate weibull distribution. |
dist.par |
Vector of parameters for the allowed distributions. Two (scale) parameters for the bivariate exponential distribution and four (2 shape parameters and 2 scale parameters) for the bivariate weibull distribution: (shape1, scale1, shape2, scale2). See details below. |
model.cens |
Model for censorship. Possible values are "uniform" and "exponential". |
cens.par |
Parameter for the censorship distribution. Must be greater than 0. |
beta |
Vector of two regression parameters for the two covariates. |
lambda |
Parameter for an exponential distribution. An exponential distribution is assumed for the baseline hazard function. |
The bivariate exponential distribution, also known as Farlie-Gumbel-Morgenstern distribution is given by
for and
. Where the marginal distribution functions
and
are exponential with scale parameters
and
and correlation parameter
,
.
The bivariate Weibull distribution with two-parameter marginal distributions. It's survival function is given by
Where and each marginal distribution has shape parameter
and a scale parameter
,
.
An object with two classes, data.frame
and TDCM
.
To accommodate time-dependent effects, we used a counting process data-structure, introduced by Andersen and Gill (1982).
In this data-structure, apart the time-fixed covariates (named covariate
), an individual's survival data is expressed by three variables:
start
, stop
and event
. Individuals without change in the time-dependent covariate (named tdcov
) are represented by only one line of data,
whereas patients with a change in the time-dependent covariate must be represented by two lines.
For these patients, the first line represents the time period until the change in the time-dependent covariate;
the second line represents the time period that passes from that change to the end of the follow-up.
For each line of data, variables start
and stop
mark the time interval (start, stop) for the data,
while event is an indicator variable taking on value 1 if there was a death at time stop, and 0 otherwise.
More details about this data-structure can be found in papers by (Meira-Machado et al., 2009).
Artur Araújo, Luís Meira Machado and Susana Faria
Anderson, P.K., Gill, R.D. (1982). Cox's regression model for counting processes: a large sample study. Annals of Statistics, 10(4), 1100-1120. doi:10.1214/aos/1176345976
Cox, D.R. (1972). Regression models and life tables. Journal of the Royal Statistical Society: Series B, 34(2), 187-202. doi:10.1111/j.2517-6161.1972.tb00899.x
Johnson, M. E. (1987). Multivariate Statistical Simulation, John Wiley and Sons.
Johnson, N., Kotz, S. (1972). Distribution in statistics: continuous multivariate distributions, John Wiley and Sons.
Lu J., Bhattacharya G. (1990). Some new constructions of bivariate weibull models. Annals of Institute of Statistical Mathematics, 42(3), 543-559. doi:10.1007/BF00049307
Meira-Machado, L., Cadarso-Suárez, C., De Uña- Álvarez, J., Andersen, P.K. (2009). Multi-state models for the analysis of time to event data. Statistical Methods in Medical Research, 18(2), 195-222. doi:10.1177/0962280208092301
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
Therneau, T.M., Grambsch, P.M. (2000). Modelling survival data: Extending the Cox Model, New York: Springer.
tdcmdata <- genTDCM(n=1000, dist="weibull", corr=0.8, dist.par=c(2,3,2,3), model.cens="uniform", cens.par=2.5, beta=c(-3.3,4), lambda=1) head(tdcmdata, n=20L) library(survival) fit1<-coxph(Surv(start,stop,event)~tdcov+covariate,data=tdcmdata) summary(fit1) tdcmdata2 <- genTDCM(n=1000, dist="exponential", corr=0, dist.par=c(1,1), model.cens="uniform", cens.par=1, beta=c(-3,2), lambda=0.5) head(tdcmdata2, n=20L) fit2<-coxph(Surv(start,stop,event)~tdcov+covariate,data=tdcmdata2) summary(fit2)
tdcmdata <- genTDCM(n=1000, dist="weibull", corr=0.8, dist.par=c(2,3,2,3), model.cens="uniform", cens.par=2.5, beta=c(-3.3,4), lambda=1) head(tdcmdata, n=20L) library(survival) fit1<-coxph(Surv(start,stop,event)~tdcov+covariate,data=tdcmdata) summary(fit1) tdcmdata2 <- genTDCM(n=1000, dist="exponential", corr=0, dist.par=c(1,1), model.cens="uniform", cens.par=1, beta=c(-3,2), lambda=0.5) head(tdcmdata2, n=20L) fit2<-coxph(Surv(start,stop,event)~tdcov+covariate,data=tdcmdata2) summary(fit2)
Generation of survival data from a time-homogeneous Markov model.
genTHMM(n, model.cens, cens.par, beta, covar, rate)
genTHMM(n, model.cens, cens.par, beta, covar, rate)
n |
Sample size. |
model.cens |
Model for censorship. Possible values are "uniform" and "exponential". |
cens.par |
Parameter for the censorship distribution. Must be greater than 0. |
beta |
Vector of three regression parameters for the three transitions: (beta_12,beta_13,beta_23). |
covar |
Parameter for generating the time-fixed covariate. An uniform distribution is used. |
rate |
Vector of dimension three. We assume an exponential baseline hazard function with constant hazard rate for each transition. |
An object with two classes, data.frame
and THMM
.
For generating survival data from the THMM model, the counting process data structure must contain the following variables:
id
, time
, state
, covariate
. Each patient is identified by id.
The variable time
represents time for each interval of follow-up while variable state
denotes the state of the individual.
Variable covariate
is the (time-fixed) covariate to be studied in the regression model.
Individuals without change in the time dependent covariate are represented by two lines of data,
whereas patients with a change in the time-dependent covariate must be represented by three lines.
Artur Araújo, Luís Meira Machado and Susana Faria
Jackson, C. (2011). Multi-State Models for Panel Data: The msm Package for R. Journal of Statistical Software, 38(8), 1–28. doi:10.18637/jss.v038.i08
Meira-Machado, L., Cadarso-Suárez, C., De Uña- Álvarez, J., Andersen, P.K. (2009). Multi-state models for the analysis of time to event data. Statistical Methods in Medical Research, 18(2), 195-222. doi:10.1177/0962280208092301
Meira-Machado L., Faria S. (2014). A simulation study comparing modeling approaches in an illness-death multi-state model. Communications in Statistics - Simulation and Computation, 43(5), 929-946. doi:10.1080/03610918.2012.718841
Meira-Machado, L., Sestelo M. (2019). Estimation in the progressive illness-death model: a nonexhaustive review. Biometrical Journal, 61(2), 245–263. doi:10.1002/bimj.201700200
Therneau, T.M., Grambsch, P.M. (2000). Modelling survival data: Extending the Cox Model, New York: Springer.
thmmdata <- genTHMM( n=100, model.cens="uniform", cens.par=80, beta= c(0.09,0.08,-0.09), covar=80, rate= c(0.05,0.04,0.05) ) head(thmmdata, n=20L)
thmmdata <- genTHMM( n=100, model.cens="uniform", cens.par=80, beta= c(0.09,0.08,-0.09), covar=80, rate= c(0.05,0.04,0.05) ) head(thmmdata, n=20L)