NO.PZ2015120604000154
问题如下:
Which of the following situation is least appropriate for using the paired comparisons test? All the populations are supposed to be normally distributed.
选项:
A. Anastasia wants to test whether mean annual returns over the last forty years are equal for an candy company's stock and an oil company's bond. She assumes the both returns have equal variances.
B. Blanche Brown wants to test if the mean monthly returns over the last three years are equal for an airline's stock and an medical company's stock. She assumes the both returns are with equal variances.
C. Lauren Lee wants to test if the mean monthly returns over the last five years are equal for a beer company's stock and an oil company's stock. He assumes the both returns are with equal variances.
解释:
A is correct.
The returns of bond and stock are relatively independent. The paired comparisons test requires samples are not independent. Stock returns are all related to market returns, so the samples of B and C are both likely dependent.
这道题考两个mean比较,这个要求难道不是: 独立的两个总体,unknown population variance嘛。test statistics用的是Sp 这里答案为什么多了一个要求,test的两个总体必须相关(not independent)?啥意思