1. A college conducted a study on the number of hours students claim to study per week. The school's student governor said that it is 28 hours per week. If 80 students in the college were surveyed and their average is 27.3 hours per week with a standard deviation of 4.1 hours, is there a sufficient evidence that the student governor's claim is not true at the a = 0.05 level of significance? 2. A provincial health center says that they believe that people in their province are becoming less healthy with an average body mass index of 23.5 kg/m with a population standard deviation of 4.5 kg/m?. A recent survey conducted involving a random sample of 60 residents and their average BMI is 22.5 kg/m?. Do you think the health center has a much higher average BMI? Use the level of significance a= 0.05. 3. Chef Giselle claims that the average meal cost of her usual clients is Php 180. In order to test her own claim, she took a random sample of 30 receipts and computed the mean cost of Php 210 with a standard deviation of Php 25. Can it be concluded that the mean cost of her clients is higher than Php 180 at 99% confidence level? 4. The daily yield for a chemical plant of Engr. Pantaleon has averaged 880 tons for several years. The quality control manager wants to know if this average has changed. She randomly selects 50 days and records an average yield of 871