1 Recycling one ton of newspaper saves 15 trees. 2  Every ton of newspaper recycled saves 4100 kWh or enough energy to power a TV for 31 hours. 3  Recycling a soda can saves 96 percent of the energy used to make a can from ore and produces 95 percent less air pollution and 97 percent less water pollution. Recycling one ton of cardboard saves over nine cubic yards of landfill space. 2  Number of landfills in operation in 1978: 14,000; in 1988: 7,924; in 2001: 1,858; in 2006: 1,754. 3  Recycling one ton of newspaper saves 15 trees. 4  Every ton of newspaper recycled saves 4100 kWh or enough energy to power a TV for 31 hours.
Once the standard error is calculated, the confidence interval is determined by multiplying the standard error by a constant that reflects the level of significance desired, based on the normal distribution. The constant for 95 percent confidence intervals is 1.96.
This is called a point estimate of h. If the sample is large, H will be a good estimate of h, but by itself it does not tell you how good it is. A 95% confidence interval is a different kind of estimate. It consists of two numbers L (lower) and U (upper), which are derived from the sample in some way without knowledge of the unknown h (or any other unknown parameters) . The interval (L, U) is supposed to contain the unknown h.