In an university, a 1-in-150 systematic sample of students is selected in order to estimate the total amount spent on food during the first semester in the population of students registered in this university. The data are shown in Table 1. (a) Estimate the total amount spent on food during the first semester. (b) Construct an 95% confidence interval for the total amount spent on food during the first semester. You may assume that the students appeared in a random order on the sampling frame