Dear Allstat members,
I am involved in the design stages of a study which aims to relate
measurements of lung function to exposure to a particular pollutant
for a small group of subjects (20 or 30). Both lung function and
personal exposure will be recorded daily on continuous scales
of measurement for 60 days.
I will need a regression analysis taking account of the autocorrelation
between the lung function measurements. A similar study looked at
deviation from the mean lung function by subtracting a subject's
mean lung function from the rest of his/her measurements.
I am aware that I will have to investigate a number of possible lags
for the pollutant measure.
I know the mean and range of the likely pollutant exposures. I also
have an estimate and confidence intervals for the effect of a unit
increase in pollutant on lung function found in a similar study.
Does anyone have any additional suggestions for the analysis
required?
Does anyone know how to perform a power calculation for this
type of study?
I would appreciate any references relating to either an
appropriate analysis or power calculations.
Thank you,
Gordon Prescott
Department of Public Health
University of Aberdeen
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