One-sample t test
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Variable | Obs Mean Std. Err. Std. Dev. [95% Conf. Interval]
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A | 21 -.0010844 .000277 .0012696 -.0016623 -.0005065
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mean = mean(A) t = -3.9141
Ho: mean = 0 degrees of freedom = 20
Ha: mean < 0 Ha: mean != 0 Ha: mean > 0
Pr(T < t) = 0.0004 Pr(|T| > |t|) = 0.0009 Pr(T > t) = 0.9996
上面是ttest A=0的 结果。请问, “Ha: mean > 0 ; Pr(T > t) = 0.9996”是什么意思?Pr()中的T和t分别代表什么?为什么mean不为0的概率为0.0009,而mean>0的概率却是0.9996?
感谢!~~~