Revival: Biological Effects of Low Level Exposures to Chemical and Radiation (1992)

136 BIOLOGICAL EFFECTS OF LOW LEVEL EXPOSURES

Table 7.7. Probability of Observing a Significantly Lower Risk in an Exposed Group, by Relative Risk and Expected Number of Cases in the

Exposed Group When the Relative Risk is Unity

Relative Risk

Expected Cases

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

i

o o o o o o o o o o

4

67

45

30

20

14

9

6

4

3

2

6

88

66

46

31

20

13

8

5

3

2

8

99

92

78

60

43

29

19

12

7

4

10

100

95

82

63

44

29

17

10

5

3

12

100

99

93

79

61

42

27

16

9

5

14

100

99

94

80

60

40

24

13

7

3

16

100

100

97

89

72

51

32

18

9

4

18

100

100

98

89

71

48

29

15

7

3

20

100

100

99

94

79

58

36

19

9

4

22

100

100

100

96

85

65

43

24

11

5

24

100

100

100

96

84

63

39

20

9

3

26

100

100

100

98

89

70

45

24

11

4

28

100

100

100

99

92

75

51

28

13

5

30

100

100

100

99

92

73

47

24

10

4

32

100

100

100

99

94

78

52

28

12

4

34

100

100

100

100

96

82

57

31

13

5

36

100

100

100

100

96

80

54

28

11

3

38

100

100

100

100

97

84

58

31

12

4

40

100

100

100

100

98

87

62

34

14

4

42

100

100

100

100

9f?

89

66

37

15

5

44

100

100

100

100

98

88

63

33

13

4

46

100

100

100

100

99

90

67

36

14

4

48

100

100

100

100

99

92

70

39

15

4

50

100

100

100

100

99

94

73

42

17

5

Note:

Rounded to nearest percent. Test statistic is observed Poisson-distributed count of cases in exposed group. Nominal probability of 5% in lower tail.