What is the critical F value for a sample of four observations in the numerator and seven in the denominator? Use a one-tailed test and the .01 significance level. can you show step by step of how you got the answer. Solution For a a sample of four observations in the numerator and seven in the denominator using a one- tailed test and the .01 significance level the critical F value is: F(4-1,7-1,0.01) =F(3,6,0.01) =9.780.