1-In a sample of 123 hip surgeries of a certain type, the average surgery time was 136.9 minutes with a standard deviation of 22.6 minutes. Construct a 95% confidence interval for the mean surgery time for this procedure.
2-Six measurements were made of the mineral content (in percent) of spinach, with the following results. It is reasonable to assume that the population is approximately normal.19.1, 20.8, 20.8, 21.4, 20.5, 19.7Construct a 95% confidence interval for the mean mineral content.
3-The National Health Statistics Reports described a study in which a sample of 360 one-year-old baby boys were weighed.Their mean weight was 25.5 pounds with a standard deviationof 5.3 pounds. A pediatrician claims that the mean weight of one-year-old boys is greater than 25 pounds. Do the data provide convincing evidence that the pediatrician's claim is true at the 0.01 level of significance?