need help finding th re z score. not understanding how to calculate the answer.

Question Help A cold medicine lists 600 milligrams of acetaminophen per fluid ounce as an active ingredient. A test of 65 one-ounce samp medicine finds that the mean amount of acetaminophen for the sample is 595 milligrams with a standard deviation of 21 mil Test the claim that the medicine does not contain the required amount of acetaminophen. Use a 0.05 significance level. State the null and alternative hypotheses. O A. Ho: H= 600 milligrams B. Hot - 600 milligrams Ha: H 600 milligrams VC. Ho: H= 600 milligrams D Hosp = 600 milligrams Ha: u # 600 milligrams Hatu = 600 milligrams Find the z-score. N ( Round to two decimal places as needed . )