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.
To achieve a significance level of 0.05 for a two-sided test, the absolute value of the test statistic (| z |) must be greater than or equal to the critical value 1.96 (which corresponds to the level 0.025 for a one-sided test).n the above example, the value 0.0082 would result in rejection of the null hypothesis at the 0.01 level. The probability that this is a mistake -- that, in fact, the null hypothesis is true given the z-statistic -- is less than 0.01.