x****t
发帖数: 1729 | 1 图是这个样子的。
question is: is the change in daily sales on Apr 29th statistically
significant? if so, what's the P-value?
数据是10/1/2012 － 9/15/2013.
这个算是compare mean 还是compare proportion？
具体应该怎么算呢？在R里应该用哪个command？ | t*****w
发帖数: 254 | 2 by eyeball, it is clear that the means before or after Apr 29th are
statistically different.
ttest(x1, x2)
x1 is before and x2 is after Apr 29th . | x****t
发帖数: 1729 | 3 直接ttest(x1, x2)就可以了么？需要设后面的参数么？
var.equal = ？, mu = ？, conf.level = 0.95, alternative = ？" | x****t
发帖数: 1729 | 4 用图回答问题：
Is the change in daily sales on 4/29/13 is due to a shift in the proportion
of male-vs-female customers?
如果但从4/29那天和前一天看，男女比例看起来是一样的。但之前和之后，男女比例的
确变化了。那这题应该怎么回答？英语没学好，搞不懂到底要比较什么。 |
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