问题描述
我对 TTestIndPower 类的 statsmodels API 感到困惑。
在
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函数中，绘制的观察数是样本总数还是每组的样本数？
解决方法
每组。
这是我用 statsmodels 生成的 power_plot
from statsmodels.stats.power import TTestIndPower
panalysis = TTestIndPower()
panalysis.plot_power(
dep_var="nobs",nobs=np.arange(5,101),effect_size=np.arange(0.5,1.5,.2),alpha=0.01,ax=ax,)
这是对 R 的确认，效果大小 (es) 为 0.7
> library(pwr)
> pwr.t.test(power = 0.8,sig.level = 0.01,d = 0.7)
Two-sample t test power calculation
n = 49.35336
d = 0.7
sig.level = 0.01
power = 0.8
alternative = two.sided
NOTE: n is number in *each* group