From a list of all passengers onboard at the time of the col
From a list of all passengers onboard at the time of the collision, groups were formed with ten names in each group. Then three of these groups were were selected using simple random sampling without replacement. The thirty passengers from the three selected groups are in the table below. Cells with an * indicate that this information is not known.
How many randomly selected passengers would have to be selected to estimate the age of all passengers to within five years with 90% confidence?
| LASTNAME | FIRSTNAME | GENDER | AGE | CLASS | BOARDED | STATUS |
| Bucknell | Emma | Female | 59 | First | Cherbourg | Survived |
| Carter | William | Male | 36 | First | Southampton | Survived |
| Crosby | Edward | Male | 70 | First | Southampton | Died |
| Daniel | Robert | Male | 27 | First | Southampton | Survived |
| Douglas | Mary | Female | 27 | First | Cherbourg | Survived |
| Guggenheim | Benjamin | Male | 46 | First | Cherbourg | Died |
| Harris | Henry | Male | 45 | First | Southampton | Died |
| Pears | Edith | Female | 22 | First | Southampton | Survived |
| Smith | Lucien | Male | 24 | First | Cherbourg | Died |
| Stephenson | Martha | Female | 52 | First | Cherbourg | Survived |
| Cameron | Clear | * | 35 | Second | Southampton | Survived |
| Corbett | Irene | Female | 30 | Second | Southampton | Died |
| Hocking | Samuel | Male | 36 | Second | Southampton | Died |
| Knight | Robert | Male | 39 | Second | Belfast | Died |
| Norman | Robert | Male | 28 | Second | Southampton | Died |
| Padron-Manent | Julian | Male | 26 | * | Cherbourg | Survived |
| Toomey | Ellen | Female | 48 | Second | Southampton | Survived |
| Trout | Jessie | * | 26 | Second | Southampton | Survived |
| West | Constance | Female | 4 | Second | Southampton | Survived |
| Williams | Charles | Male | 23 | Second | Southampton | Survived |
| Asplund | Johan | Male | 23 | Third | Southampton | Survived |
| Bradley | Bridget | Female | 22 | Third | Queenstown | Survived |
| Daly | Margaret | Female | 30 | Third | Queenstown | Survived |
| Devaney | Margaret | Female | 19 | Third | Queenstown | Survived |
| Dowdell | Elizabeth | Female | 31 | * | Southampton | Survived |
| Jirjis | Shaniini | * | 22 | Third | Cherbourg | Survived |
| Madsen | Fridtjof | Male | 24 | Third | Southampton | Survived |
| Strandberg | Ida | Female | 22 | Third | Southampton | Died |
| Torfa | Assad | Male | 20 | Third | Cherbourg | Died |
| Touma | Gerios | Male | 8 | Third | Cherbourg | Survived |
Solution
Getting the standard deviation of the group using technology, we get
s = 14.08203
Note that
n = z(alpha/2)^2 s^2 / E^2
where
alpha/2 = (1 - confidence level)/2 = 0.05
Using a table/technology,
z(alpha/2) = 1.644853627
Also,
s = sample standard deviation = 14.08203
E = margin of error = 2
Thus,
n = 134.1297307
Rounding up,
n = 135 [ANSWER]

