Some common strategies for treating hypertensive patients bynonpharmacologic methods include (1) weight reduction and (2)trying to get the patient to relax more by meditational or othertechniques. These strategies were evaluated by randomizinghypertensive patients to four groups who receive the followingtypes of nonpharmacologic therapy: Group 1: patients receivecounselling for both weight reduction and meditation. Group 2:patients receive counselling for weight reduction but not formeditation. Group 3: patients receive counselling for meditationbut not for weight reduction. Group 4: patients receive nocounselling at all. 20 hypertensive patients were assigned atrandom to each of the four groups, and the change in diastolicblood pressure (DBP) was recorded in these patients after a 1-monthperiod. These data are summarized as follows:
Group n Mean change in DBP    sd of change (baseline -followup) (mm Hg)

1 20 8.6 6.2

2 20 5.3    5.4

3 20 4.9    7.0

4 20 1.1    6.5

(a)Complete the following ANOVA table:
Source of variation    DF Sum of Squares Mean Square   F-statistic p-value

Model (between group) _________ 565.35 _______   _______    < 0.05

Error (Within group)    __________ ________ ______________________ _________

Total    3583.31    ___________ _____________   ________    ____________

(b)Interpret this p-value. Be sure to clearly state what is beingtested and what this means in the context of the problem ofinterest. Comment on our ability to draw causal inference in thissetting.