Changed `Sex` field description

```
> head(data_second)
  Survived PassengerId                         Name Sex Age Pclass     Fare Embarked
1        0         460        O'Connor, Mr. Maurice   0  NA      3     7.75        Q
2        1         461          Anderson, Mr. Harry   0  48      1 2,655.00        S
3        0         462          Morley, Mr. William   0  34      3     8.05        S
4        0         463            Gee, Mr. Arthur H   0  47      1     38.5        S
5        0         464 Milling, Mr. Jacob Christian   0  48      2       13        S
6        0         465           Maisner, Mr. Simon   0  NA      3     8.05        S
```

Mr. looks like male to me, while 
```
> head(data_second[which(data_second$Sex == 1),])
   Survived PassengerId                                         Name Sex   Age Pclass    Fare
11        1         470                Baclini, Miss. Helene Barbara   1  0.75      3 19.2583
14        1         473      West, Mrs. Edwy Arthur (Ada Mary Worth)   1 33.00      2   27.75
15        1         474 Jerwan, Mrs. Amin S (Marie Marthe Thuillard)   1 23.00      2 13.7917
16        0         475                  Strandberg, Miss. Ida Sofia   1 22.00      3  9.8375
21        1         480                     Hirvonen, Miss. Hildur E   1  2.00      3 12.2875
25        1         484                       Turkula, Mrs. (Hedwig)   1 63.00      3  9.5875
```

Looks like female