Answer:
2.1115
Step-by-step explanation:
Significance level α = 2.5/100= 0.025
degree of freedom for factor A = 4(5-1)
degree of freedom for factor B=3(4-1)
degree of freedom for interaction =degree of freedom for factor A x degree of freedom for factor B = 4 x 3= 12
total degree of freedom = (5 x 4 x 5)-1 = 99
error degree of freedom= 99-(4+3+12)
= 80
F-critical value = F₀.₀₂₅, ₁₂, ₈₀
= 2.1115