Three professors examined awareness of four widely disseminated retirement rulesamong employees at the University of Utah. These rules provide simple answers toquestions about retirement planning (see R. N. Mayer, C.

D. Zick, and M. Glaittle,"Public Awareness of Retirement Planning Rules of Thumb," Journal of PersonalFinance, 2011 10(1), 12–35). At the time of the investigation, there were approximately10,000 benefited employees, and 3,095 participated in the study. Demographic datacollected on these 3,095 employees included gender, age (years), education level(years completed), marital status, household income ($), and employment category. a) Briefly describe the population of interest. [1 mark] b) Briefly describe the sample that was collected. [1 mark] c) Indicate whether each of the demographic variables mentioned is categoricalor numerical. [3 marks]