Final answer:
The upper-tail critical value of F for a two-tailed test with α=0.05, n1=16, and n2=21 is approximately 2.4919.
Step-by-step explanation:
The upper-tail critical value of F for a two-tailed test with α=0.05, n1=16, and n2=21 can be found using the F distribution table. The degrees of freedom for the numerator and denominator are (n1-1) and (n2-1) respectively. In this case, the degrees of freedom are 15 and 20. Consulting the F distribution table, the upper-tail critical value for α=0.05 and degrees of freedom 15 and 20 is approximately 2.4919.