Suppose a larger study is planned. How many participants are needed to detect a difference of 1 unit in mean balance score with 80% power if the number of participants in each group is intended to be the same and a two-sided test is used with α = .05?

Rheumatology

A study was conducted [12] comparing muscle function between patients with rheumatoid arthritis (RA) and osteoarthritis (OA). A 10-point scale was used to assess balance and coordination in which a high score indicates better coordination. The results were as shown in Table 8.20 for 36 RA patients and 30 OA patients.

Table 8.20: Comparison of balance scores for patients with RA vs. OA

 

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Mean balance sd score 3.0 36 30 3.4 RA 2.5 2.8 OA