a)
|
crew |
first |
second |
third |
| survival rate= |
24.0% |
62.2% |
41.4% |
25.2% |
b)
Ho: group and survival are related
H1: group and survival are not related
c)
| Chi-Square Test of independence |
|
|
|
|
|
|
Observed Frequencies |
|
|
|
|
crew |
first |
second |
third |
|
|
Total |
| alive |
212 |
202 |
118 |
178 |
|
|
710 |
| dead |
673 |
123 |
167 |
528 |
|
|
1491 |
| Total |
885 |
325 |
285 |
706 |
|
|
2201 |
|
|
|
|
|
|
|
|
|
Expected frequency of a cell = sum of row*sum of column / total
sum |
|
Expected Frequencies |
|
crew |
first |
second |
third |
|
|
Total |
| alive |
885*710/2201=285.484 |
325*710/2201=104.839 |
285*710/2201=91.935 |
706*710/2201=227.742 |
|
|
710 |
| dead |
885*1491/2201=599.516 |
325*1491/2201=220.161 |
285*1491/2201=193.065 |
706*1491/2201=478.258 |
|
|
1491 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Total |
885 |
325 |
285 |
706 |
|
|
2201 |
|
|
|
|
|
|
|
|
|
(fo-fe)^2/fe |
|
| alive |
18.9148 |
90.0461 |
7.390 |
10.864 |
|
|
|
| dead |
9.0071 |
42.8791 |
3.519 |
5.173 |
|
|
|
Chi-Square Test Statistic,χ² = Σ(fo-fe)^2/fe
=Â Â 187.7932Â Â
    Â
Level of Significance =Â Â 0.05Â Â
Number of Rows =Â Â 2Â Â
Number of Columns =Â Â 4Â Â
Degrees of Freedom=(#row - 1)(#column -1) = (2- 1 ) * ( 4- 1 )
=Â Â 3Â Â
    Â
p-Value =Â Â 0.0000 [Excel function:
=CHISQ.DIST.RT(χ²,df) ]
Decision:   p-value < α , Reject Ho
There is strong evidence that the survival rates are not
all the same
in group first class, survival rate is highest
