Random wikipedia links of interest
2. Demographics of the People’s Republic of China. A few quotes from the article:
a) “Census data obtained in 2000 revealed that 119 boys were born for every 100 girls, and among China’s “floating population” the ratio was as high as 128:100. These situations led the government in July 2004 to ban selective abortions of female fetuses. It is estimated that this imbalance will rise until 2025–2030 to reach 20% then slowly decrease.”
b) “Average household size (2005) 3.1; rural households 3.3; urban households 3.0.
Average annual per capita disposable income of household (2005): rural households Y 3,255 (U.S.$397), urban households Y 10,493 (U.S.$1,281).”
c) A map of the population density (darker squares have higher density):
The ‘average population density’ of 137/km2 is not an all that interesting variable. The Gobi desert is not a nice place for humans to live: The temperature variation in the area is extreme, ranging from –40°C in the winter to +50°C in the summer.
3. Cost overrun. An excerpt:
“Cost overrun is common in infrastructure, building, and technology projects. One of the most comprehensive studies  of cost overrun that exists found that 9 out of 10 projects had overrun, overruns of 50 to 100 percent were common, overrun was found in each of 20 nations and five continents covered by the study, and overrun had been constant for the 70 years for which data were available. For IT projects, an industry study by the Standish Group (2004) found that average cost overrun was 43 percent, 71 percent of projects were over budget, over time, and under scope, and total waste was estimated at US$55 billion per year in the US alone.”
4. Tensor. This is difficult stuff.