needing help on questions 19 and 20? how do you construct a confidence interval?

19 . Suppose you work for a city health agency and are asked to estimate the mean caffeine content per five ounces for a coffee shop . You find that a random sample of 45 five - ounce servings has a mean caffeine content of 88 milligrams . Suppose the population standard deviation is 30 milligrams ( 15 points possible ) . Construct a 99 % confidence interval ( 5 points ) Construct a 95% confidence interval ( 5 points ) provide a confidence statement using the 95 % confidence interval ( 5 points ) 20 . The average time spent studying for STA 210 was more than 120 minutes per week among previous STA 210 students . A sample of 66 students has an average time of 112 minutes Suppose the population standard deviation is 3 . 5 minutes . ( 35 points possible ) State the hypothesis ( 5 points )Calculate the test statistic ( 5 points ) Give the p-value ( 5 points d . Provide the appropriate alpha value at 95% confidence ( 5 points (5 points Use the p - value to make your decision about the hypothesis ( 5 points ) rite a concluding statement ( interpret the result ) ( 10 points