题目
Problem
A scientist is investigating the size of shells at various beach locations. She selects four beach locations and takes a random sample of shells from each of these beaches. She classifies each shell as large or small. Her results are summarised in the following table.
| Size of shell | A | B | C | D | Total |
|---|---|---|---|---|---|
| Large | 68 | 69 | 96 | 81 | 314 |
| Small | 28 | 55 | 64 | 39 | 186 |
| Total | 96 | 124 | 160 | 120 | 500 |
Test, at the 10% significance level, whether the size of shell is independent of the beach location.
[7]
题目中文翻译
一名科学家正在研究不同海滩地点的贝壳大小。她选择四个海滩地点，并从每个海滩随机抽取贝壳样本。她将每个贝壳分类为大或小。她的结果汇总在下表中。
| 贝壳大小 | A | B | C | D | 总计 |
|---|---|---|---|---|---|
| 大 | 68 | 69 | 96 | 81 | 314 |
| 小 | 28 | 55 | 64 | 39 | 186 |
| 总计 | 96 | 124 | 160 | 120 | 500 |
在 10% 显著性水平下，检验贝壳大小是否与海滩地点相互独立。