1 The total project cost for a Trex deck ranges between $1,500 and $2,200 for a 250sf deck. 2  Trex Select of basic quality averages approximately $7/sf.  Trex Enhance of higher quality is approximately $8/sf.
When the hypothesized value is zero then there is a simple relationship between hypothesis testing and confidence intervals: If the interval contains zero then the null hypothesis cannot be rejected at the stated level of confidence. If the interval does not contain zero then the null hypothesis can be rejected.
A test of the null hypothesis that the difference between two responses measured on the same statistical unit has a mean value of zero. For example, suppose we measure the size of a cancer patient's tumor before and after a treatment.