Introductory Biostatistics

For body mass index:

BMI Level Odds Ratio

22.5–24.9 1.41

25 þ 1.39

General odds ratio is 1.22.

1.26 For duration of unprotected intercourse:

Years Odds Ratio

2–9 0.94

10–14 1.04

15 þ 1.54

General odds ratio is 1.21, showing an upward trend of risks.

For history of infertility:

History Odds Ratio

Yes, no drug use 1.13

Yes, with drug use 3.34

General odds ratio is 1.33, showing an upward trend of risks.

1.27 For boys:

Maternal Age Odds Ratio

21–25 0.97

26–30 0.67

30 þ 0.43

General odds ratio is 0.62, showing an downward trend of risks, de-

creasing with increasing maternal age.

For girls:

Maternal Age Odds Ratio

21–25 0.80

26–30 0.81

30 þ 0.62

General odds ratio is 0.84, showing an downward trend of risks, de-

creasing with increasing maternal age, but the trend is weaker than that

for boys.

1.28 Sensitivity¼ 0 :650; specificity¼ 0 :917.

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