1. Topic: Experimental Design
Digit Ratio
Topic: Experimental Design
Group Four
Members: Chan Yong Ming, Kwek Zi Wei Bernetta, Peh Ching Hui Timothy
Presenter: Chan Yong Ming

2. What is Digit Ratio?

3. https://i2. wp. com/newsimg. bbc. co

4. Lower Ratio Higher Ratio

5. Findings

6. Calculating Digit Ratio
Subject A
D2 is 6 cm
D4 is 10 cm
Ratio D2/D4 = 6/10 = 0.6
Subject B
D2 is 9 cm
D4 is 10 cm
Ratio D2/D4 = 9/10 = 0.9
Lower Ratio
Higher Ratio

7. ACTIVITY TIME!

8. Lower Ratio Higher Ratio
Higher Risk of Prostate Cancer
Higher Risk of Depression
Increased Aggression
More Superstitious
Mathematical Ability
Higher Exam Score Among Males
Leadership
Higher Verbal Fluency

9. Assigned Reading
Group four: Read “Digit Ratio" in Wikipedia (and its references if necessary)

10. Outline Background Timeline of Research Study Other Examples
Advantages
Limitations
Suitable Experimental Design?

11. Phenomenon Explained
Ratio affected by exposure to androgens while in uterus
Sexually dimorphic
Correlation between digit ratio and various physical & behavioural traits
Varies between different ethnic groups

12. Timeline of Research Study
1983: Correlation between digit ratio & assertiveness in women
Dr Wilson proposed skeletal structure and personality simultaneously affected by sex hormone levels
1998: Digit Ratio marker of prenatal sex hormones
Sex difference in digit ratios was present in two-year-old children
2011: Digit Ratio strictly due to exposure in utero androgens
Digit ratio of mice affected by balance of androgen to estrogen signaling during development

13. OBSERVATIONAL
RETROSPECTIVE
STUDY!!!

14. Retrospective Study Type of Observational Study
Collects data from past records
No follow-up on subjects

15. Other Examples

16. Advantages Cost friendly Conducted on a smaller scale
Less Time Consuming

17. Limitations Results may be biased
Confounding factors may affect study results

18. What makes a good Experimental Design?

19. Good Experimental Design
Fair and Unbiased
Blocking factors that may influence measurements or results
Randomizing factors that cannot be blocked

20. Suitable Experimental Design
Randomize
Pick about 50 pregnant women from ethnic group each using random sampling (Stratified Random Sampling)
Blocked factors
Similar lifestyle and suitable food choices (Not alter hormone levels)
Measure the growth of fetus for 13 weeks in the womb and digit ratio when born

21. “It is the weight, not numbers of experiments that is to be regarded
“It is the weight, not numbers of experiments that is to be regarded.” - Issac Newton