Homework 6.A Survival Odds of Titanic Passengers Using Zelig 5

Library Setup

Loading Packages

Objective

The goal of this first assignment is to reimplement the code from slides 5.2-5.18 of lecture 6 using Zelig 5. In the lecture notes Zelig 4 was used, however for this assignment the code will be repeated but using zelig 5. Since simulations are involved, some of the numbers might vary.

Loading the Data, Selecting the Variables, and Cleaning the Data

Preview Titanic Statistics

 pclass    survived     survival          sex           age              sibsp       
 1st:282   Yes:425   Min.   :0.0000   female:386   Min.   : 0.1667   Min.   :0.0000  
 2nd:261   No :618   1st Qu.:0.0000   male  :657   1st Qu.:21.0000   1st Qu.:0.0000  
 3rd:500             Median :0.0000                Median :28.0000   Median :0.0000  
                     Mean   :0.4075                Mean   :29.8132   Mean   :0.5043  
                     3rd Qu.:1.0000                3rd Qu.:39.0000   3rd Qu.:1.0000  
                     Max.   :1.0000                Max.   :80.0000   Max.   :8.0000  
     parch             fare            name              cabin                  embarked  
 Min.   :0.0000   Min.   :  0.00   Length:1043        Length:1043        Cherbourg  :212  
 1st Qu.:0.0000   1st Qu.:  8.05   Class :character   Class :character   Queenstown : 50  
 Median :0.0000   Median : 15.75   Mode  :character   Mode  :character   Southampton:781  
 Mean   :0.4219   Mean   : 36.60                                                          
 3rd Qu.:1.0000   3rd Qu.: 35.08                                                          
 Max.   :6.0000   Max.   :512.33                                                          
      surv      
 Min.   :1.000  
 1st Qu.:1.000  
 Median :2.000  
 Mean   :1.593  
 3rd Qu.:2.000  
 Max.   :2.000  

Interaction Model Using Zelig 5

z.out1 <- zlogit$new()
z.out1$zelig(survival ~ age + sex*pclass + fare, data = titanic)
summary(z.out1)

Model: 

Call:
z.out1$zelig(formula = survival ~ age + sex * pclass + fare, 
    data = titanic)

Deviance Residuals: 
    Min       1Q   Median       3Q      Max  
-3.0634  -0.6641  -0.4943   0.4336   2.4941  

Coefficients:
                    Estimate Std. Error z value            Pr(>|z|)
(Intercept)        4.8978215  0.6131092   7.988 0.00000000000000137
age               -0.0387245  0.0068044  -5.691 0.00000001262563680
sexmale           -3.8996177  0.5015659  -7.775 0.00000000000000755
pclass2nd         -1.5923247  0.6024844  -2.643             0.00822
pclass3rd         -4.1382715  0.5601819  -7.387 0.00000000000014976
fare              -0.0009058  0.0020509  -0.442             0.65874
sexmale:pclass2nd -0.0600076  0.6372949  -0.094             0.92498
sexmale:pclass3rd  2.5019110  0.5479901   4.566 0.00000498035051247

(Dispersion parameter for binomial family taken to be 1)

    Null deviance: 1409.99  on 1042  degrees of freedom
Residual deviance:  931.45  on 1035  degrees of freedom
AIC: 947.45

Number of Fisher Scoring iterations: 5

Next step: Use 'setx' method

Age Effect Using Zelig 5

z.out1$setrange(age=0:80)
z.out1$sim()
z.out1$graph()

Fare Effect Using Zelig 5

The maximum fare value was acquired from the statistics above.

z.out1$setrange(fare=0:513)
z.out1$sim()
z.out1$graph()

Sex Differences and Simulated First Difference Using Zelig 5

z.out1$setx(sex="male")
z.out1$setx1(sex="female")
z.out1$sim()
fd <- z.out1$get_qi(xvalue="x1", qi="fd")
summary(fd)

       V1        
 Min.   :0.1311  
 1st Qu.:0.2259  
 Median :0.2554  
 Mean   :0.2549  
 3rd Qu.:0.2840  
 Max.   :0.3846  

plot(z.out1)

Testing Class Variations in Sex Difference Using Zelig 5

1st Class

z5.1st <- zlogit$new()
z5.1st$zelig(survival ~ age + sex*pclass + fare, data = titanic)
z5.1st$setx(sex = "male", pclass = "1st") 
z5.1st$setx1(sex = "female", pclass = "1st")
z5.1st$sim()
plot(z5.1st)

Second Class

z5.2nd <- zlogit$new()
z5.2nd$zelig(survival ~ age + sex*pclass + fare, data = titanic)
z5.2nd$setx(sex = "male", pclass = "2nd") 
z5.2nd$setx1(sex = "female", pclass = "2nd")
z5.2nd$sim()
plot(z5.2nd)

Third Class

z5.3rd <- zlogit$new()
z5.3rd$zelig(survival ~ age + sex*pclass + fare, data = titanic)
z5.3rd$setx(sex = "male", pclass = "3rd") 
z5.3rd$setx1(sex = "female", pclass = "3rd")
z5.3rd$sim()
plot(z5.3rd)

Putting FDs Into One Table

d1 <- z5.1st$get_qi(xvalue="x1", qi="fd")
d2 <- z5.2nd$get_qi(xvalue="x1", qi="fd")
d3 <- z5.3rd$get_qi(xvalue="x1", qi="fd")
  
dfd <- as.data.frame(cbind(d1, d2, d3))
head(dfd)

Sort by Class

tidd <- dfd %>% 
  gather(class, simv, 1:3)
head(tidd)

Sort by Group

tidd %>% 
  group_by(class) %>% 
  summarise(mean = mean(simv), sd = sd(simv))

Sort by Plot

ggplot(tidd, aes(simv)) + geom_histogram() + facet_grid(~class)