Table 3.
Consider two women who have the same history of smoking and weight change and are receiving the same intervention (exercise or wellness). Patient A is observed at time t − 1 but drops out of the study and is not seen at time t, while patient B remains in the study and is observed at time t. | ||||
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If the probability that patient B smoked during week t is p, what is your best guess (median) for the probability that patient A (who dropped out) smoked during week t? Also provide a lower bound and upper bound on reasonable values. | ||||
Treatment | Prob. observed patient B smokes (p) | Best guess | Lower bound | Upper bound |
for the probability that the unobserved Patient A smokes | ||||
Wellness | 25 % | 50 % | 40 % | 60 % |
Wellness | 50 % | 70 % | 60 % | 80 % |
Wellness | 75 % | 95 % | 90 % | 100 % |
Exercise | 25 % | 50 % | 40 % | 60 % |
Exercise | 50 % | 70 % | 60 % | 80 % |
Exercise | 75 % | 95 % | 90 % | 100 % |
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If the observed patient B has an expected percentage weight change from baseline of w at week t, what is your best guess (median) for the expected percentage weight change from baseline at week t for patient A who dropped out? Also provide a lower bound and upper bound on reasonable values. | ||||
For reference, the average weight change was 2.4% and the standard deviation was 2.6%. Also, negative values are allowed if it is believed that the patient will have lost weight since baseline. | ||||
Treatment | Weight change for observed patient B (w) |
Best guess | Lower bound | Upper bound |
for the expected weight change of the unobserved Patient A | ||||
Wellness | 2.5 % | 2 % | 0 % | 5 % |
Exercise | 2.5 % | 1.5 % | 0 % | 4 % |