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.
If you fail to reject the null hypothesis then you have observed a sample that is plausible assuming the null is true. the conclusion is that the null is plausible. you cannot conclude the null is true. Consider the hypothesis as a trial against the null hypothesis. the data is evidence against the mean.