臧老师，“Estimating sample size in functional MRI (fMRI) neuroimaging studies: statistical power analyses.”（J Neurosci Methods. 2002 Aug 30;118(2):115-128.）摘要中有“ Our analyses suggested that for a liberal threshold of 0.05, about 12 subjects were required to achieve 80% power at the single voxel level for typical activations. At more realistic thresholds, that approach those used after correcting for multiple comparisons, the number of subjects doubled to maintain this level of power.”，是不是说在单体素水平，P取0.05，12例就可以满足统计需求？
如您所说，脑影像学研究体素非常多，这个研究结果是否就不适用了？
Submitted by ZangYF on Thu, 02/06/2014 - 11:16 Permalink
Re: 静息态功能磁共振研究是否需要计算样本量？
目前脑影像学的研究，观察变量（即体素）非常多，很难对每个体素计算effect size，我们对某个脑区的假设通常也不是特别强，再者，不同研究之间的可重复性并不是特别好，我认为这些可能是估算样本量在脑成像研究中不太普及的原因。
Submitted by water on Tue, 02/11/2014 - 06:58 Permalink
Re: 静息态功能磁共振研究是否需要计算样本量？
谢谢臧老师。 费用高大概也是个原因。那是不是说样本量没有严格要求？
Submitted by ZangYF on Thu, 02/13/2014 - 17:12 Permalink
Re: 静息态功能磁共振研究是否需要计算样本量？
费用较高可能也是一个原因，但估计不是主要原因。
Submitted by water on Fri, 02/21/2014 - 20:53 Permalink
Re: 静息态功能磁共振研究是否需要计算样本量？
臧老师，“Estimating sample size in functional MRI (fMRI) neuroimaging studies: statistical power analyses.”（J Neurosci Methods. 2002 Aug 30;118(2):115-128.）摘要中有“ Our analyses suggested that for a liberal threshold of 0.05, about 12 subjects were required to achieve 80% power at the single voxel level for typical activations. At more realistic thresholds, that approach those used after correcting for multiple comparisons, the number of subjects doubled to maintain this level of power.”，是不是说在单体素水平，P取0.05，12例就可以满足统计需求？
如您所说，脑影像学研究体素非常多，这个研究结果是否就不适用了？