Statistics and probalbility

(a) An officer was appointed by the Malaysia Energy Commission to study the difference between old and new electricity meter for Malaysia households. He collected the electric usage before and after changing the electricity meter from 2000 households in Perak and Selangor. The summary of the data is shown by the histograms and box plats below. Electric Usage for New arid Old meter 160 200 240 280 320 360 400 New Old 140 120- 100 Frequency 80 60 40 20 0- 160 200 240 280 320 360 400 Electric Usage Panel variable: Meter Electric Usange for old and new meter 450 400 350- 300 Bectric Usage 250 200 150- New Old Meter (i) State the population of the above study. Hence, comment on the error of the above sample. (3 marks) (ii) State the variable(s) of the above study. Provide the type of data and level of the measurement of the variable(s). (6 marks)