I have a fundamental question about applying ANOVA.
Suppose we are testing 4 drugs which reduce blood pressure. Our experiment contains 4 drugs + 1 Placebo. We give these to 3 types of patients (moderate, high, very high). Each drug is given to 18 patients which have equal number of the above types. A total of 18x5 = 90 patients are tested for over a year. Everyday we take 3 readings of their Blood pressure (morning, afternoon, night).
Now after a year, we have the individual readings, daily reading (average of 3 individual readings), weekly reading (average of all readings in a week) and similarly monthly reading.
If I do a between subject one-way ANOVA to find if there is a statistical difference in the means. Which readings should it be applied to? The individual readings-- in which case the DOF will be high, or the daily, weekly, month average. What is the fundamental theory which allows us to determine on which values the ANOVA should be run. Does it make a differance if we run it on different averages as against the raw values.