Make sure to state what your parameter (μ) means in context!
Random sample: Must be determined by you. Is this a random sample or random assignment in an experiment?
10% rule: Must be determined by you. Is your sample size smaller than 10% of the population?
To find our critical t* value, you can use the inverse t function on your calculator or use a table with critical t values.
Please keep in mind that you should always write your conclusion in the context of the problem.