21. i) Samples of two types of electric light bulbs were tested for (7) length of life and the following data were obtained. Type I Type II Sample 8 7 size 1234 hrs 1036 hrs Sample 36 hrs 40 hrs mean Sample S.D Is the difference in the means sufficient to warrant that type I is superior to type II regarding length of life? ii) Two sample polls of votes for two candidates A and B for a (7) public office are taken, one from among the residents of rural areas and one from the residents of urban areas. The results are given in the table. Examine whether the nature of the area is related to voting preference in this election. Votes for A B Total area Rural 620 380 1000 Urban 550 450 1000 Total 1170 1830 2000