For each of the following, calculate four degrees of freedom \(\left(d f_{\mathrm{A}}, d f_{\mathrm{B}}, d f_{\mathrm{A} \times \mathrm{B}}, d f_{\text {WG }}\right)\) and identify the three critical values of the three \(F\)-ratios \(\left(F_{\mathrm{A}}, F_{\mathrm{B}}, F_{\mathrm{A} \times \mathrm{B}}\right)\) (assume \(\alpha=.05\) ).

a. \(\quad a=2, \quad b=2, \quad N_{\mathrm{AB}}=4\)

b. \(a=2, \quad b=2, \quad N_{\mathrm{AB}}=18\)

c. \(a=3, \quad b=2, \quad N_{\mathrm{AB}}=9\)

d. \(a=2, \quad b=4, \quad N_{\mathrm{AB}}=6\)