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.
The central reason we do hypothesis testing is to decide whether or not the sample data are consistent with the null hypothesis. In the second step of the procedure we identify the kind of data that is expected if the null hypothesis is true. Specifically, we identify the mean we expect if the null hypothesis is true.