题目
(a) State two conditions under which it might be more appropriate to use Spearman’s rank correlation coefficient rather than the product moment correlation coefficient.
A random sample of 10 melons was taken from a market stall. The length, in centimetres, and maximum diameter, in centimetres, of each melon were recorded. The Spearman’s rank correlation coefficient between the results was –0.673
(b) Test, at the 5% level of significance, whether or not there is evidence of a correlation. State clearly your hypotheses and the critical value used.
The product moment correlation coefficient between the results was –0.525
(c) Test, at the 5% level of significance, whether or not there is evidence of a negative correlation. State clearly your hypotheses and the critical value used.
题目中文翻译
(a) 写出在什么情况下，使用 Spearman 秩相关系数可能比使用积差相关系数更合适的两个条件。
从一个市场摊位抽取了 10 个瓜的随机样本。记录了每个瓜的长度（厘米）和最大直径（厘米）。 结果的 Spearman 秩相关系数为 –0.673。
(b) 在 5% 显著性水平下，检验是否有相关性的证据。请清楚写出原假设和所用临界值。
结果的积差相关系数为 –0.525。
(c) 在 5% 显著性水平下，检验是否有负相关的证据。 请清楚写出原假设和所用临界值。