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

What is Digit Ratio?

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Lower Ratio Higher Ratio http://www.handresearch.com/pics/zheng-2D-4D-digit-ratio.jpg

Findings https://en.wikipedia.org/wiki/Digit_ratio

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

ACTIVITY TIME!

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

Assigned Reading Group four: Read “Digit Ratio" in Wikipedia (and its references if necessary) http://en.wikipedia.org/wiki/Digit_ratio

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

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

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

OBSERVATIONAL RETROSPECTIVE STUDY!!!

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

Other Examples http://www.clipartkid.com/images/0/free-to-use-public-domain-television-clip-art-page-2-fO43ZJ-clipart.png http://media1.s-nbcnews.com/j/newscms/2014_01/828416/141230-smoking-cigarette-mn-1300_4f8fb05ea1449949f932ba2a3c3508e1.nbcnews-ux-2880-1000.jpg

Advantages Cost friendly Conducted on a smaller scale Less Time Consuming

Limitations Results may be biased Confounding factors may affect study results

What makes a good Experimental Design?

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

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

“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  http://www.nceagletimes.com/wp-content/uploads/2016/11/Isaac-Newton.jpg

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