Revision: Human development index

Thanks to tutor2u for this summary
http://www.tutor2u.net/economics/reference/human-development-index-hdi?utm_medium=email&utm_campaign=Economics%20daily%20digest%20Fri%201st%20April%202016&utm_content=Economics%20daily%20digest%20Fri%201st%20April%202016+CID_aae44e53e9d5705fa50b0fa5bfb55ab6&utm_source=CampMonitor&utm_term=Human%20Development%20Index%20HDI%20Study%20presentations%20This%20is%20an%20updated%20revision%20presentation%20on%20the%20Human%20Development%20Index