FAQ/PRsq - CBU statistics Wiki
location: FAQ / PRsq

Sample sizes for selected values of R-squared and different numbers of groups in a one-way anova

The table below gives the total sample size required for 90% and 80% power for upto 8 groups in a one-way anova. In each case the type I error is taken as 5%. The rows in bold correspond to Cohen's rules of thumb for small, medium and large effect sizes.

90% power

80% power

R-squared

K=3

K=4

K=5

K=6

K=7

K=8

K=3

K=4

K=5

K=6

K=7

K=8

0.010

1269

1424

1550

1656

1750

1840

969

1096

1200

1290

1372

1448

0.059

207

232

255

270

287

304

159

180

200

216

231

240

0.10

117

132

144

154

163

172

90

103

113

122

130

137

0.138

84

96

105

114

119

128

66

76

80

90

98

104

0.15

76

85

93

100

106

111

58

66

73

79

84

89

0.20

54

61

67

72

77

81

42

49

54

58

62

65

0.25

42

47

52

56

59

63

33

38

42

45

48

51

0.30

33

38

42

45

48

51

27

30

34

37

39

42

0.35

28

31

34

37

40

42

22

25

28

31

33

35

0.40

23

27

29

32

34

36

19

22

24

26

28

30

0.45

20

23

25

27

29

31

16

19

21

23

25

27

0.50

17

20

22

24

26

27

14

16

18

20

22

23

0.55

15

17

19

21

23

24

12

15

16

18

20

21

0.60

13

15

17

19

20

22

11

13

15

16

18

19

None: FAQ/PRsq (last edited 2013-03-08 10:17:14 by localhost)