Type I error rates.

Sequenced sample size varies from 1,000 to 4,000, while the gene length varies from 500 to 3,000 nucleotides. Type I error rate is estimated on 10,000 replicates at significance levels 5% and 1%.
Abbreviation: FWCST, the proposed functional variant weighted continuous sum test; FWBST, the proposed functional variant weighted binary sum test; ST, the sum test without weighting; GWWS, the group-wise weighted sum test [16]; CMC, the combined multivariate collapsing test [15].