F & t Test Tool
The Federal Highway Administration (FHWA) engaged Weris under contract number DTFH61-13-R-00037 to develop a software tool that state transportation departments and contractors can use in order to validate contractor test data. Regulation 23 CFR Part 637B – Quality Assurance Procedures for Construction allows contractor tests to be used as part of acceptance decisions if they are validated by verification tests.
The software developed by Weris determines risks depending on sample size and, alternatively, establishes the required sample size given specified acceptable risk levels. The tool demonstrates risks using F-test, a comparison of two variances of two populations, and the t-test, a statistical test involving confidence limits for the random variable of a t-distribution that is used in testing hypotheses about means of distributions when the standard deviations are unknown.
The tool helps state transportation departments and contractors make the right choice in optimizing risks with the number of samples.