Skip to main content
. Author manuscript; available in PMC: 2010 Sep 1.
Published in final edited form as: Dig Dis Sci. 2009 Mar 17;55(3):709–715. doi: 10.1007/s10620-009-0772-x

Table 3.

Number of Subjects (per treatment group or per disease/phenotype) Needed to Detect Listed Effect Size with ≥80% Power (2-sided α=0.05) Based on a Two-Sample t-Test.

Response CV inter (%) Effect size (%) demonstrable N per group required
Compliance Pr50
mmHg
22.8 25 15
30 11
35 8
Fasting Tone, ml 30.8 25 25
30 18
35 14
First 30 minute
postprandial change
in tone vs fasting, ml
59.1 25 89
30 62
35 46
Pain Threshold,
mmHg
31 25 26
30 18
35 14
Gas sensation rating
with 36 mmHg
distension
41.9 25 46
30 32
35 24
Pain sensation rating
with 36 mmHg
distension
56.3 25 81
30 57
35 42