The separate assumptions of the textbook model imply that the errors are independently, identically, and normally distributed for fixed effects models, that is, that the errors () are independent and
ðə sˈɛpɹət ɐsˈʌmpʃənz ʌvðə tˈɛkstbʊk mˈɑːdəl ɪmplˈaɪ ðætðɪ ˈɛɹɚz ɑːɹ ˌɪndᵻpˈɛndəntli, aɪdˈɛntɪkli, ænd nˈoːɹməli dˈɪstɹɪbjˌuːɾᵻd fɔːɹ fˈɪkst ɪfˈɛkts mˈɑːdəlz, ðæt ˈɪz, ðætðɪ ˈɛɹɚz ɑːɹ ˌɪndᵻpˈɛndənt ænd