Final answer:
The expected assessment data with a lithium level of 0.8 would include fine hand tremors, thirst, and polyuria.
Step-by-step explanation:
With a lithium level of 0.8, the expected assessment data would be fine hand tremors. Fine hand tremors are a common side effect of lithium therapy. Other assessment data may include thirst and polyuria, which are symptoms of dehydration caused by lithium-induced diabetes insipidus. Muscle weakness is not typically associated with a lithium level of 0.8, and diarrhea is not a common side effect of lithium therapy.