Directions: Solve the following problems. Show your complete solutions. 1. The GPA of randomly selected Grade 11 students at ABC University is 1.45 and it's population standard deviation is 0.56. a. Find the 98% confidence intervals for the GPA of the entire Grade 11 students. b. Find the 95% confidence intervals for the GPA of the entire Grade 11 students. 2. An economist claims that the population standard deviation of the monthly income of all the families that belong to the poverty level is Php2,800.00. A group of researchers surveyed 300 families that belong to the poverty level and obtained a mean monthly income of Php3,700.00. Assuming that the monthly income of the families is approximately normally distributed, find: a. The 80% confidence interval of the monthly income of all the families that belong to the poverty level. b. The 90% confidence interval of the monthly income of all the families that belong to the poverty level. c. The 99% confidence interval of the monthly income of all the families that belong to the poverty level