Nod means "Yes" and Shake means "No" ?

Make a research either from internet or survey of people understanding about nodding and shaking head.
Some countries may indicate that nod means "no" and shake means "yes".
Explain each country that doesn't express their agreement and disagreement through nodding and shaking head, in what way they express their agreement and disagreement?

Do the research in group of three(3) ! Present the findings in front of the class and don't forget to bring the paper to be collected. :D