Table 1

Examples of sample sizes required with varying assumptions and a Type I Error of 0.05
Number of patients required in each arm
Power SD = 9.4[25] SD = 5.34[35]
5% difference* 7% difference** 5% difference* 7% difference**
80% 56 29 19 10
90% 75 39 25 13

*Difference to reach clinically significant target weight loss of <5% (as studies have shown weight loss of 9.3-9.75%) [25,35].

**Difference seen with pre-treatment dietary counselling intervention [35].

Brown et al.

Brown et al. BMC Nursing 2014 13:17   doi:10.1186/1472-6955-13-17

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