Note on Griffiths 9.37

Ignore Griffith's answer to part (d) (his equations 9.203). What
he wants are the transmitted fields, but he has chosen the phase of the
amplitude E_{to }to be zero, which is not possible in general,
if the incident field amplitude has zero phase-- the usual
assumption. Your (correct) expressions will look a bit more
complicated.

Proceed with (e) and (f) using the correct fields.