请问Level 1-Mock74，３４题？ following, economic, between, factors, product

JoeyDVivre

34. Which of the following factors would least likely intensify competition within an
industry?
A. Many suppliers.
B. Ease of entry.
C. Commodity product.
答案是Ａ，我觉Ａ也是加重竞争的呀，给解释一下．
25. An analyst gathered information about three economic variables, He noted that
whenever variable A increased by one unit, variable B increased by 0,5 units but
variable C decreased by 0.5 units. The correlation between variables A and B and
the correlation between variables A and C respectively, are closest to:
Correlation between variables A and B Correlation between variables A and C
A 0.5 ‐1.0
B 0.5 ‐0.5
C 1.0 ‐1.0
A. Answer A
B. Answer B
C. Answer C
答案是ｃ，为何ｂ不对呀？

apf薛老师

我觉得是这样，自己认为：
34 问得是最不会加剧竞争的是什么，首先自由进出是肯定被排除的，理由很简单，正是因为可以自由进出，完全竞争和垄断竞争厂商长期才没有利润可言，所以自由进入肯定是被排除的，公共品我觉得是个干扰项，我不太清楚公共品对竞争的影响，貌似书里也没有相关说明吧，至于厂商数量增多，确实会加剧竞争，但是只要厂商串谋，仍然可以做到像一个垄断厂商那样，opec就是类似的例子，相比自由进出，厂商数量对竞争的加剧影响更小一点。

25 这个很简单，你把题目看一下就好了，他说a每增加1，b就增加0.5，同时c也减少0.5，证明ab\ac有严格的线性关系，即b=0.5a+xx c=-0.5a+xx，答案自然是1，对相关系数理解有些偏差吧。