Final answer:
In the sentence provided, no hyphens are necessary. Hyphens are primarily used to connect words serving as a single modifier before a noun. Examples demonstrate the correct addition or omission of hyphens in various contexts.
Step-by-step explanation:
Add hyphens to compound adjectives where necessary. In the sentence 'Ever since I moved to California last year, I've started eating a surprisingly large number of avocados,' no hyphens are needed because the modifiers 'surprisingly large' are not functioning as a single modifier before a noun but are adverbs modifying an adjective.
Hyphens are used in English to join two or more words serving as a single modifier before a noun, clarifying how the modifiers function. In the examples given, we can correct the sentences as follows: Paint-splattered tie (Before a noun, the compound adjective needs a hyphen). Ragged-old clothes (No hyphen necessary because 'ragged' is not modifying 'old').'
Scared-stiff mouse (Compound adjective before a noun, needs a hyphen). Empty plastic water bottles (No hyphen necessary because both words separately modify 'water bottles'). Dog-eared book (Before the noun 'book' a hyphen is needed to link the compound adjective).