Table 1

Overview over sample sizes in the included studies.

Number of groups

Number of participants

Min number in group

Max number in group


N

Valid

198

178

118

119

Missing

22

42

102

101

Mean

8.4

45.5

5.2

8.7

Median

5

32

5

8

Range

1 to 96

3 to 279

1 to 13

3 to 20


Carlsen and Glenton BMC Medical Research Methodology 2011 11:26   doi:10.1186/1471-2288-11-26

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