Composite decking is increasingly popular, as it requires little maintenance. Options include polyethylene (with an average cost per square foot of $7.82), polypropylene (average cost per square foot, $8.68) and polyvinyl chloride or PVC (average cost per square foot, $7.50 hollow core, $9.48 solid core.) Pros. Composite materials are very durable, and won't splinter or rot.
Two-sample t-tests for a difference in mean involve independent samples or unpaired samples. Paired t-tests are a form of blocking, and have greater power than unpaired tests when the paired units are similar with respect to noise factors that are independent of membership in the two groups being compared.
If Leveneâs test indicates that the variances are not equal across the two groups (i.e., p-value small), you will need to rely on the second row of output, Equal variances not assumed, when you look at the results of the Independent Samples t Test (under the heading t-test for Equality of Means).