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.
Type I error. When the null hypothesis is true and you reject it, you make a type I error. The probability of making a type I error is Î±, which is the level of significance you set for your hypothesis test.An Î± of 0.05 indicates that you are willing to accept a 5% chance that you are wrong when you reject the null hypothesis.he probability of making a type II error is Î², which depends on the power of the test. You can decrease your risk of committing a type II error by ensuring your test has enough power. You can do this by ensuring your sample size is large enough to detect a practical difference when one truly exists.