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.
Using a right tail test and alpha = 0.05 the critical t is: 2.13. Since the test statistic (1.98) lies to the left of the critical t (2.13), we fail to reject the null hypothesis that the difference between pre-test score and post-test score is zero..If the test statistic lies in the critical region, reject the null hypothesis in favor of the alternative hypothesis, if it does not, then you would fail to reject the hull hypothesis. To save time and effort the table below relates critical z values to alpha levels and type test.