How is the standard of living in united states better than that of the africans? Specifically (nigeria). Discuss.

It depends what you call better. Junk food is not better when we have so many overweight people. Health is not better when most Americans over 60 are taking about 20 different meds to keep their cholestrol, blood pressure and whatever else down. As far as health goes check with the Okinawa and other Asian places and the Chapota Tribe and you will find quality.
As far as material things some of the richer people have big beautiful houses that they have to work hard to keep up and then they are always running to Wal Mart or where ever to buy a bunch of stuff they don't need to clutter up the house. Then they throw away stuff that is nicer than I can afford.
Many of the poorer people want and expect everything handed to them and then they waste it rather than take care of it. I can say that because I live right there and watch them let their stuff get ruined and then cry for more.
They say Canada and Europes money is worth more than the USA's now.
Then there is the violence.
We have our freedom but the politically correct people are always trying do something to fix that in a negative way.
America does have some beautiful land and people and other qualities.
So it depends what you call better.