Capítulo 4 - Modelos de Regressão Paramétricos

 temp<-c(65,156,100,134,16,108,121,4,39,143,56,26,22,1,1,5,65)
 cens<-rep(1,17)
 lwbc<-c(3.36,2.88,3.63,3.41,3.78,4.02,4.00,4.23,3.73,3.85,3.97,4.51,4.54,5.00,5.00,4.72,5.00)
 dados<-cbind(temp,cens,lwbc)
 require(survival)
 dados<-as.data.frame(dados)
 i<-order(dados$temp)
 dados<-dados[i,]
 ajust1<-survreg(Surv(dados$temp, dados$cens)~dados$lwbc, dist='exponential')
 x<-dados$lwbc
 t<-dados$temp
 bo<- ajust1$coefficients[1]
 b1<- ajust1$coefficients[2]
 res<- t*exp(-bo-b1*x)
 ekm <- survfit(Surv(res,dados$cens)~1, type=c("kaplan-meier"))
 summary(ekm)
 par(mfrow=c(1,2))
 plot(ekm, conf.int=F, lty=c(1,1), xlab="resíduos", ylab="S(e) estimada")
 res<-sort(res)
 exp1<-exp(-res)
 lines(res,exp1,lty=3)
 legend(2,0.8, lty=c(1,3), c("Kaplan-Meier","Exponencial(1)"), lwd=1, bty="n", cex=0.7)
 st<-ekm$surv
 t<-ekm$time
 sexp1<-exp(-t)
 plot(st, sexp1, xlab="S(e) - Kaplan-Meier", ylab= "S(e) - Exponencial(1)", pch=16)


 dados<-as.data.frame(cbind(temp,cens,lwbc))
 ajust1<-survreg(Surv(dados$temp, dados$cens)~dados$lwbc, dist='exponential')
 ajust1
 x1<-4.0
 temp1<-0:150
 ax1<-exp(ajust1$coefficients[1]+ajust1$coefficients[2]*x1)
 ste1<-exp(-(temp1/ax1))
 x1<-3.0
 temp2<-0:150
 ax2<-exp(ajust1$coefficients[1]+ajust1$coefficients[2]*x1)
 ste2<-exp(-(temp2/ax2))
 par(mfrow=c(1,1))
 plot(temp1, temp1*0, pch=" ", ylim=range(c(0,1)), xlim=range(c(0,150)), xlab="Tempos", 
      ylab="S(t) estimada", bty="n")
 lines(temp1, ste1, lty=2)
 lines(temp2, ste2, lty=4)
 abline(v=100, lty=3)
 legend(10,0.3, lty=c(2,4), c("lwbc = 4.0","lwbc = 3.0"), lwd=1, bty="n")


 temp<-c(65,156,100,134,16,108,121,4,39,143,56,26,22,1,1,5,65,56,65,17,7,16,22,3,4,2,3,8,4,3,30,4,43)
 cens<-c(rep(1,17),rep(1,16))
 lwbc<-c(3.36,2.88,3.63,3.41,3.78,4.02,4,4.23,3.73,3.85,3.97,4.51,4.54,5,5,4.72,
         5,3.64,3.48,3.6,3.18,3.95,3.72,4,4.28,4.43,4.45,4.49,4.41,4.32,4.90,5,5)
 grupo<-c(rep(0,17),rep(1,16))
 require(survival)
 ekm1<-survfit(Surv(temp,cens)~grupo)
 summary(ekm1)
 st1<-ekm1[1]$surv
 time1<-ekm1[1]$time
 invst1<-qnorm(st1)
 st2<-ekm1[2]$surv
 time2<-ekm1[2]$time
 invst2<-qnorm(st2)
 par(mfrow=c(1,3))
 plot(time1, -log(st1), pch=16, xlab="tempos", ylab="-log(S(t))")
 points(time2, -log(st2))
 legend(100, 0.6, pch=c(16,1), c("Ag+","Ag-"), bty="n")
 plot(log(time1), log(-log(st1)), pch=16, xlab="log(tempos)", ylab="log(-log(S(t)))")
 points(log(time2), log(-log(st2)))
 legend(3, -1.5, pch=c(16,1), c("Ag+","Ag-"), bty="n")
 plot(log(time1), invst1,pch=16, xlab="log(tempos)", ylab=expression(Phi^-1*(S(t))))
 points(log(time2), invst2)
 legend(0.5,-1, pch=c(16,1), c("Ag+","Ag-"), bty="n")


 temp<-c(65,156,100,134,16,108,121,4,39,143,56,26,22,1,1,5,65,56,65,17,7,16,22,3,4,2,3,8,4,3,30,4,43)
 cens<-c(rep(1,17),rep(1,16))
 lwbc<-c(3.36,2.88,3.63,3.41,3.78,4.02,4,4.23,3.73,3.85,3.97,4.51,4.54,5,5,4.72,
         5,3.64,3.48,3.6,3.18,3.95,3.72,4,4.28,4.43,4.45,4.49,4.41,4.32,4.90,5,5)
 grupo<-c(rep(0,17), rep(1,16))
 dados<-as.data.frame(cbind(temp,cens,lwbc,grupo))
 attach(dados)
 require(survival)
 ajust1<-survreg(Surv(temp,cens)~1, dist='exponential')
 ajust1
 ajust2<-survreg(Surv(temp,cens)~lwbc, dist='exponential')
 ajust2
 ajust3<-survreg(Surv(temp,cens)~grupo, dist='exponential')
 ajust3
 ajust4<-survreg(Surv(temp,cens)~lwbc + grupo, dist='exponential')
 ajust4
 ajust5<-survreg(Surv(temp,cens)~lwbc + grupo + lwbc*grupo, dist='exponential')
 ajust5
 summary(ajust4)


 t<-temp
 x1<-lwbc
 x2<-grupo
 bo<-6.83
 b1<--0.7
 b2<--1.02
 res<- t*exp(-bo-b1*x1-b2*x2)
 ekm <- survfit(Surv(res,dados$cens)~1, type=c("kaplan-meier"))
 par(mfrow=c(1,2))
 plot(ekm, conf.int=F, lty=c(1,1), xlab="residuos", ylab="S(res) estimada")
 res<-sort(res)
 exp1<-exp(-res)
 lines(res, exp1, lty=3)
 legend(2, 0.8, lty=c(1,3), c("Kaplan-Meier","Exponencial(1)"), lwd=1, bty="n", cex=0.8)
 st<-ekm$surv
 t<-ekm$time
 sexp1<-exp(-t)
 plot(st, sexp1, xlab="S(res): Kaplan-Meier", ylab= "S(res): Exponencial(1)", pch=16)


 x1<-4.0
 x2<-0.0
 temp1<-0:150
 ax1<-exp(6.83-0.70*x1-1.02*x2)
 ste1<-exp(-(temp1/ax1))
 x1<-3.0
 x2<-0.0
 temp2<-0:150
 ax2<-exp(6.83-0.70*x1-1.02*x2)
 ste2<-exp(-(temp2/ax2))
 par(mfrow=c(1,2))
 plot(temp1, temp1*0, pch=" ", ylim=range(c(0,1)), xlim=range(c(0,150)), xlab="Tempos", 
      ylab="S(t) estimada", bty="n")
 lines(temp1, ste1, lty=1)
 lines(temp2, ste2, lty=2)
 legend(75, 0.8, lty=c(1,2), c("lwbc = 4.0","lwbc = 3.0"), lwd=1, bty="n", cex=0.8)
 title("Ag+")
 x1<-4.0
 x2<-1.0
 temp1<-0:150
 ax1<-exp(6.83-0.70*x1-1.02*x2)
 ste1<-exp(-(temp1/ax1))
 x1<-3.0
 x2<-1.0
 temp2<-0:150
 ax2<-exp(6.83-0.70*x1-1.02*x2)
 ste2<-exp(-(temp2/ax2))
 plot(temp1, temp1*0, pch=" ", ylim=range(c(0,1)), xlim=range(c(0,150)), xlab="Tempos", 
      ylab="S(t) estimada", bty="n")
 lines(temp1, ste1, lty=1)
 lines(temp2, ste2, lty=2)
 legend(75, 0.8, lty=c(1,2), c("lwbc = 4.0","lwbc = 3.0"), lwd=1, bty="n", cex=0.8)
 title("Ag-")


 x1<-4.0
 x2<-0.0
 temp1<-0:150
 risco1<-1/(exp(6.83-0.70*x1-1.02*x2))
 risco1<-rep(risco1, 151)
 x1<-3.0
 x2<-0.0
 temp2<-0:150
 risco2<-1/(exp(6.83-0.70*x1-1.02*x2))
 risco2<-rep(risco2, 151)
 plot(temp1,temp1*0, pch=" ", ylim=range(c(0,0.1)), xlim=range(c(0,150)), xlab="Tempo",
      ylab="Risco estimado", bty="n")
 lines(temp1, risco1, lty=1)
 lines(temp2, risco2, lty=2)
 legend(100, 0.08, lty=c(1,2), c("lwbc = 4.0","lwbc = 3.0"), lwd=1, bty="n", cex=0.8)
 title("Ag+")
 x1<-4.0
 x2<-1.0
 temp1<-0:150
 risco1<-1/(exp(6.83-0.70*x1-1.02*x2))
 risco1<-rep(risco1,151)
 x1<-3.0
 x2<-1.0
 temp2<-0:150
 risco2<-1/(exp(6.83-0.70*x1-1.02*x2))
 risco2<-rep(risco2, 151)
 plot(temp1, temp1*0, pch=" ", ylim=range(c(0,0.1)), xlim=range(c(0,150)), xlab="Tempo",
      ylab="Risco estimado", bty="n")
 lines(temp1, risco1, lty=1)
 lines(temp2, risco2, lty=2)
 legend(100, 0.08, lty=c(1,2), c("lwbc = 4.0","lwbc = 3.0"), lwd=1, bty="n", cex=0.8)
 title("Ag-")

Capítulo 5 - Modelo de Regressão de Cox

 laringe<-read.table("https://docs.ufpr.br/~giolo/Livro/ApendiceA/laringe.txt", h=T)     
 attach(laringe)
 fit4<-coxph(Surv(tempos,cens) ~ factor(estagio) + idade + factor(estagio)*idade, data=laringe, 
             x = T, method="breslow")

 Ht<-basehaz(fit4, centered=F)
 tempos<-Ht$time
 H0<-Ht$hazard
 S0<- exp(-H0)
 round(cbind(tempos,S0,H0), digits=5)

 tt<-sort(tempos)
 aux1<-as.matrix(tt)
 n<-nrow(aux1)
 aux2<-as.matrix(cbind(tempos,S0))
 S00<-rep(max(aux2[,2]),n)
  for(i in 1:n){
     if(tt[i]> min(aux2[,1])){
        i1<- aux2[,1]<= tt[i]
        S00[i]<-min(aux2[i1,2])}}
 ts0<-cbind(tt,S00)
 ts0
 
 b<-fit4$coefficients
 id<-50
 st1<-S00^(exp(b[4]*id))                # S(t|x) estágio I   e idade = 50 anos
 st2<-S00^(exp(b[1]+((b[4]+b[5])*id)))  # S(t|x) estágio II  e idade = 50 anos
 st3<-S00^(exp(b[2]+((b[4]+b[6])*id)))  # S(t|x) estágio III e idade = 50 anos
 st4<-S00^(exp(b[3]+((b[4]+b[7])*id)))  # S(t|x) estágio IV  e idade = 50 anos
 id<-65
 st11<-S00^(exp(b[4]*id))               # S(t|x) estágio I   e idade = 65 anos
 st21<-S00^(exp(b[1]+((b[4]+b[5])*id))) # S(t|x) estágio II  e idade = 65 anos
 st31<-S00^(exp(b[2]+((b[4]+b[6])*id))) # S(t|x) estágio III e idade = 65 anos
 st41<-S00^(exp(b[3]+((b[4]+b[7])*id))) # S(t|x) estágio IV  e idade = 65 anos
 
 par(mfrow=c(1,2))
 plot(tt,st1, type="s", ylim=range(c(0,1)), xlab="Tempos", ylab="S(t|x)", lty=1)
 lines(tt,st2, type="s", lty=2)
 lines(tt,st3, type="s", lty=3)
 lines(tt,st4, type="s", lty=4)
 legend(0, 0.2, lty=c(1,2,3,4), c("estágio I","estágio II","estágio III","estágio IV"), 
        lwd=1, bty="n", cex=0.7)
 title("Idade = 50 anos")

 plot(tt,st11, type="s", ylim=range(c(0,1)), xlab="Tempos", ylab="S(t|x)", lty=1)
 lines(tt,st21,type="s",lty=2)
 lines(tt,st31,type="s",lty=3)
 lines(tt,st41,type="s",lty=4)
 legend(0, 0.2, lty=c(1,2,3,4), c("estágio I","estágio II","estágio III","estágio IV"), 
        lwd=1, bty="n", cex=0.7)
 title("Idade = 65 anos")


 Ht1<- -log(st1)
 Ht2<- -log(st2)
 Ht3<- -log(st3)
 Ht4<- -log(st4)
 Ht11<- -log(st11)
 Ht21<- -log(st21)
 Ht31<- -log(st31)
 Ht41<- -log(st41)
 par(mfrow=c(1,2))
 plot(tt, Ht1, type="s", ylim=range(c(0,4)), xlab="Tempos", ylab="Risco Acumulado", lty=1)
 lines(tt, Ht2, type="s", lty=2)
 lines(tt, Ht3, type="s", lty=3)
 lines(tt, Ht4, type="s", lty=4)
 legend(0.5,3.5, lty=c(1,2,3,4), c("estágio I","estágio II","estágio III","estágio IV"),
        lwd=1, bty="n", cex=0.7)
 title("Idade = 50 anos")
 plot(tt, Ht11, type="s", ylim=range(c(0,4)), xlab="Tempos", ylab="Risco Acumulado", lty=1)
 lines(tt, Ht21, type="s", lty=2)
 lines(tt, Ht31, type="s", lty=3)
 lines(tt, Ht41, type="s", lty=4)
 legend(0.5,3.5, lty=c(1,2,3,4), c("estadio I","estágio II","estágio III","estágio IV"),
        lwd=1, bty="n", cex=0.7)
 title("Idade = 65 anos")


 desmame<-read.table("https://docs.ufpr.br/~giolo/Livro/ApendiceA/desmame.txt", h=T)
 attach(desmame)
 require(survival)
 par(mfrow=c(2,2))
 fit1<-coxph(Surv(tempo[V1==0],cens[V1==0])~1,data=desmame, x=T, method="breslow")
 ss<- survfit(fit1)
 s0<-round(ss$surv, digits=5)
 H0<- -log(s0)
 plot(ss$time, log(H0), xlim=range(c(0,20)), xlab="Tempos", ylab=expression(log(Lambda[0]*(t))),
      bty="n",type="s")
 fit2<-coxph(Surv(tempo[V1==1],cens[V1==1])~1, data=desmame, x=T, method="breslow")
 ss<- survfit(fit2)
 s0<-round(ss$surv, digits=5)
 H0<- -log(s0)
 lines(ss$time, log(H0), type="s", lty=2)
 legend(10,-3, lty=c(2,1), c("V1 = 1 (Não)","V1 = 0 (Sim)"), lwd=1,bty="n",cex=0.7)
 title("V1: Experiência Amamentação")


 leucc<-read.table("https://docs.ufpr.br/~giolo/Livro/ApendiceA/leucc.txt", h=T)
 attach(leucc)
 require(survival)
  par(mfrow=c(2,3))
 fit<-coxph(Surv(tempos[leuinic==1],cens[leuinic==1]) ~ 1, data=leucc, x = T, method="breslow")
 ss<- survfit(fit)
 s0<-round(ss$surv, digits=5)
 H0<- -log(s0)
 plot(ss$time, log(H0), xlab="Tempos", ylim=range(c(-5,1)), ylab = expression(log(Lambda[0]* (t))),
      bty="n", type="s")
 fit<-coxph(Surv(tempos[leuinic==0],cens[leuinic==0]) ~ 1, data=leucc, x = T, method="breslow")
 ss<- survfit(fit)
 s0<-round(ss$surv, digits=5)
 H0<- -log(s0)
 lines(ss$time, log(H0), type="s", lty=4)
 legend(1.5, -4, lty=c(4,1), c("leuini < 75","leuini > 75 "), lwd=1, bty="n", cex=0.8)
 title("LEUINI")

Capítulo 6 - Extensões do Modelo de Regressão de Cox

 hg2<-read.table("https://docs.ufpr.br/~giolo/Livro/ApendiceA/hg2.txt", h=T) 
 attach(hg2)
 require(survival)
 rendac<-ifelse(renda<4,1,2)
 alt<-ifelse(ialtura<120,1,2)
 fit3<-coxph(Surv(tempos,cens)~factor(raca)+factor(trauma) + factor(recemnas) + factor(rendac) +
             factor(trauma)*factor(recemnas) + strata(alt), data=hg2, method="breslow")
 summary(fit3)
 fit4<-coxph(Surv(tempos,cens)~factor(raca) + factor(trauma) + factor(rendac) + strata(alt),
             data=hg2, method="breslow")
 summary(fit4)
 cox.zph(fit4, transform="identity")
 par(mfrow=c(1,3))
 plot(cox.zph(fit4))
 H0<-basehaz(fit4, centered=F)
 H0
 H01<-as.matrix(H0[1:21,1])
 H02<-as.matrix(H0[22:39,1])
 tempo1<-H0$time[1:21]
 S01<-exp(-H01)
 round(cbind(tempo1,S01,H01), digits=5)
 tempo2<- H0$time[22:39]
 S02<-exp(-H02)
 round(cbind(tempo2,S02,H02), digits=5)
 
 par(mfrow=c(1,2))
 plot(tempo2, H02, lty=4, type="s", xlab="Tempos", xlim=range(c(10,50)), ylab=expression(Lambda[0]*(t)))
 lines(tempo1, H01, type="s", lty=1)
 legend(10, 25, lty=c(1,4), c("altura inicial < 120cm","altura inicial >= 120cm"),
 lwd=1, bty="n", cex=0.8)
 plot(c(0,tempo2),c(1,S02), lty=4, type="s", xlab="Tempos",
 ylim=range(c(0,1)), xlim=range(c(10,50)), ylab="So(t)")
 lines(c(0,tempo1),c(1,S01), lty=1, type="s")
 legend(25,0.85, lty=c(1,4), c("altura inicial < 120cm", "altura inicial>=120cm"), lwd=1, 
        bty="n", cex=0.8)


Análise gráfica dos resíduos de Cox-Snell do modelo ajustado.

 hg2a<-na.omit(hg2[,c(1:5,7)])
 rendac<-ifelse(hg2a$renda<4,1,2) 
 alt<-ifelse(hg2a$ialtura<120,1,2)
 fit4<-coxph(Surv(tempos,cens)~factor(raca) + factor(trauma) + factor(rendac) + strata(alt),
       data=hg2a, method="breslow")
 summary(fit4)
 resm<-resid(fit4, type="martingale") 
 res<-hg2a$cens-resm 
 ekm <- survfit(Surv(res, hg2a$cens)~1)
 summary(ekm)
 
 par(mfrow=c(1,2))
 plot(ekm, mark.time=F, conf.int=F, xlab="resíduos", ylab="S(e) estimada")
 res<-sort(res)
 exp1<-exp(-res)
 lines(res, exp1, lty=3)
 legend(1, 0.8, lty=c(1,3), c("Kaplan Meier","Exponencial(1)"), lwd=1, bty="n", cex=0.7)
 st<-ekm$surv
 t<-ekm$time
 sexp1<-exp(-t)
 plot(st, sexp1, xlab="S(e): Kaplan-Meier", ylab= "S(e): Exponencial(1)", pch=16)

Capítulo 8 - Censura Intervalar e Dados Grupados

 mang1<-read.table("https://docs.ufpr.br/~giolo/Livro/ApendiceA/dadmang.txt", h=T)
 attach(mang1)
 fit1<-glm(y~-1+int1+int2+int3+int4+int5+int6+int7+int8+int9+int10+int11+int12+
       factor(bloco,levels=5:1)+as.factor(copa), family=binomial(link="cloglog"))
 
 cf<-as.vector(fit1$coefficients[1:12])  #(gama_i)*
 gi<-exp(-exp(cf))                       #(gama_i)

 S0<-gi
  for(i in 1:11){
   S0[i+1]<-prod(gi[1:(i+1)])}
 S0<-c(1,S0)                             # So(t)
 
 cf1<-fit1$coefficients[18:22] 
 Sc1<-S0 
 Sc2<-(S0)^exp(cf1[1])
 Sc3<-(S0)^exp(cf1[2]) 
 Sc4<-(S0)^exp(cf1[3]) 
 Sc5<-(S0)^exp(cf1[4])
 Sc6<-(S0)^exp(cf1[5])
 
 t<-c(0,2,3,4,10,12,14,15,16,17,18,19,21)
 cbind(t,Sc1,Sc2,Sc3,Sc4,Sc5,Sc6)
 par(mfrow=c(1,1))
 plot(t,Sc1, type="s", lty = 1, ylim=range(c(0,1)), xlab="Tempo de Vida (anos)",
      ylab="Sobrevivência Estimada")
 points(t,Sc1,pch=21) 
 lines(t,Sc2,type="s",lty=2)
 points(t,Sc2,pch=15) 
 lines(t,Sc3,type="s",lty=3)
 points(t,Sc3,pch=14) 
 lines(t,Sc4,type="s",lty=4)
 points(t,Sc4,pch=8)  
 lines(t,Sc5,type="s",lty=5)
 points(t,Sc5,pch=16) 
 lines(t,Sc6,type="s",lty=6)
 points(t,Sc6,pch=17)
 legend(1, 0.5, lty=c(1,2,3,4,5,6), pch=c(21,15,14,8,16,17), c("Copa 1-Extrema","Copa 2-Oliveira",
        "Copa 3-Pahiri","Copa 4-Imperial","Copa 5-Carlota","Copa 6-Bourbon"), bty="n", cex=0.9)
 title("Modelo de Riscos Proporcionais")


 mang1<-read.table("https://docs.ufpr.br/~giolo/Livro/ApendiceA/dadmang.txt", h=T)
 attach(mang1)
 fit2<-glm(y~-1+int1+int2+int3+int4+int5+int6+int7+int8+int9+int10+int11+int12+
       factor(bloco,levels=5:1)+as.factor(copa), family=binomial(link="logit"))

 cf<-fit2$coefficients[1:12]       #(gama_i)*
 gi<-exp(cf)                       #(gama_i)
 
 cf1<-fit2$coefficients[18:22]
 qi1<-(1/(1+gi))
 Slc1<-qi1
 for(i in 1:11){
   Slc1[i+1]<-prod(qi1[1:(i+1)])}
 Slc1<-c(1,Slc1)                   #S(t) copa 1
 qi2<-(1/(1+gi*exp(cf1[1])))
 Slc2<-qi2
 for(i in 1:11){
   Slc2[i+1]<-prod(qi2[1:(i+1)])}
 Slc2<-c(1,Slc2)                   #S(t) copa 2
 qi3<-(1/(1+gi*exp(cf1[2])))
 Slc3<-qi3
 for(i in 1:11){
   Slc3[i+1]<-prod(qi3[1:(i+1)])}
 Slc3<-c(1,Slc3)                   #S(t) copa 3
 qi4<-(1/(1+gi*exp(cf1[3])))
 Slc4<-qi4
 for(i in 1:11){
   Slc4[i+1]<-prod(qi4[1:(i+1)])}
 Slc4<-c(1,Slc4)                   #S(t) copa 4
 qi5<-(1/(1+gi*exp(cf1[4])))
 Slc5<-qi5
 for(i in 1:11){
   Slc5[i+1]<-prod(qi5[1:(i+1)])}
 Slc5<-c(1,Slc5)                   #S(t) copa 5
 qi6<-(1/(1+gi*exp(cf1[5])))
 Slc6<-qi6
 for(i in 1:11){
   Slc6[i+1]<-prod(qi6[1:(i+1)])}
 Slc6<-c(1,Slc6)                   #S(t) copa 6
 
 t<-c(0,2,3,4,10,12,14,15,16,17,18,19,21)
 cbind(t,Slc1,Slc2,Slc3,Slc4,Slc5,Slc6)
 par(mfrow=c(1,1))
 plot(t, Slc1, type="s", lty=1, ylim=range(c(0,1)), xlab="Tempo de Vida (anos)",
      ylab="Sobrevivência Estimada")
 points(t, Slc1, pch=21)
 lines(t, Slc2, type="s", lty=2)
 points(t, Slc2, pch=15)
 lines(t, Slc3, type="s", lty=3)
 points(t, Slc3, pch=14)
 lines(t, Slc4, type="s", lty=4)
 points(t, Slc4, pch=8)
 lines(t, Slc5, type="s", lty=5)
 points(t, Slc5, pch=16)
 lines(t, Slc6, type="s", lty=6)
 points(t, Slc6, pch=17)
 legend(1, 0.5, lty=c(1,2,3,4,5,6), pch=c(21,15,14,8,16,17), c("Copa 1-Extrema","Copa 2-Oliveira",
        "Copa 3-Pahiri", "Copa 4-Imperial","Copa 5-Carlota","Copa 6-Bourbon"), bty="n", cex=0.9)
 title("Modelo Logístico")