题目
Problem
There are three bus companies in a city. The council is investigating whether the buses reliably arrive at their destination on time. The results from random samples of buses from each company are summarised in the following table.
| Bus company | |||||
|---|---|---|---|---|---|
| A | B | C | Total | ||
| Arrival | Early | 22 | 22 | 10 | 54 |
| Arrival | On time | 30 | 52 | 42 | 124 |
| Arrival | Late | 28 | 26 | 18 | 72 |
| Total | 80 | 100 | 70 | 250 |
Test, at the 5% significance level, whether the reliability of buses is independent of bus company.
[7]
题目中文翻译
某城市有三家公交公司。市政部门正在调查公交车是否能可靠地准时到达目的地。从每家公司公交车的随机样本得到的结果概括如下表。
| 公交公司 | |||||
|---|---|---|---|---|---|
| A | B | C | 合计 | ||
| 到达情况 | 提前 | 22 | 22 | 10 | 54 |
| 到达情况 | 准时 | 30 | 52 | 42 | 124 |
| 到达情况 | 晚点 | 28 | 26 | 18 | 72 |
| 合计 | 80 | 100 | 70 | 250 |
在 5% 显著性水平下，检验公交车的可靠性是否与公交公司相互独立。