A small pilot study may not give a precise estimate of data variability. If the data from the larger study turns out to be substantially larger, then realised power may be much lower than anticipated.
Where a pilot model is used we can extract uncertainty information about the variance components (including residuals).
A small pilot study may not give a precise estimate of data variability. If the data from the larger study turns out to be substantially larger, then realised power may be much lower than anticipated.
Where a pilot model is used we can extract uncertainty information about the variance components (including residuals).