Introductory Biostatistics

4.9

Assay Parameter

95% Confidence

Interval

Dupont’s Sensitivity ð 0 : 820 ; 1 : 0 Þ

Specificity ð 0 : 971 ; 1 : 0 Þ

Cellular Product’s Sensitivity not available

Specificity ð 0 : 935 ; 0 : 990 Þ

Note:Sample sizes are very small here.

4.10 Personnel Exposure 95% Confidence Interval

Physicians Frequent ð 0 : 121 ; 0 : 299 Þ

Infrequent ð 0 : 023 ; 0 : 135 Þ

Nurses Frequent ð 0 : 133 ; 0 : 291 Þ

Infrequent ð 0 : 038 ; 0 : 136 Þ

4.11 (a)Proportion:ð 0 : 067 ; 0 : 087 Þ; odds ratio:ð 1 : 44 ; 2 : 05 Þ.

4.12 (a)Proportion:ð 0 : 302 ; 0 : 374 Þ; odds ratio:ð 0 : 15 ; 0 : 44 Þ.

4.13

Event Gender

95% Confidence

Interval for OR

Myocardial infarction Men ð 0 : 69 ; 1 : 28 Þ

Women ð: 30 ;: 99 Þ

Coronary death Men ð: 39 ;: 83 Þ

Women ð: 12 ; 1 : 25 Þ

No clear evidence of e¤ect modification, intervals are overlapped.

4.14 Religion Group 95% Confidence Interval for OR

Protestant ð 0 : 31 ; 0 : 84 Þ

Catholic ð 1 : 58 ; 13 : 94 Þ

Others ð 0 : 41 ; 1 : 51 Þ

The odds ratio for the Catholics is much higher.

4.15 (a)Proportion:ð 0 : 141 ; 0 : 209 Þ; odds ratio:ð 1 : 06 ; 1 : 93 Þ.

4.16 (a) Odds ratio¼

ð 177 Þð 31 Þ

ð 11 Þð 249 Þ

¼ 2 : 0

exp ln 2: 0 G 1 : 96

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

1

177

þ

1

31

þ

1

11

þ

1

249

!r

¼ð 0 : 98 ; 4 : 09 Þ

ANSWERS TO SELECTED EXERCISES 511