1. A study is conducted to determine whether Company ABC retains its workers longer than Company XYZ. The study finds that in a sample of 12 workers at Company ABC their average time with the company is 4.2 years. A sample of 10 workers at Company XYZ finds that the average time with the company is 3.5 years. It is known from previous records that both companies are normally distributed with population standard deviation for Company ABC was 1.5 years and Company XYZ was 1.2 years. (a) In order to test the above proposition, state which statistics distribution you will use and justify your choice. (4) (b) Test the above proposition at the 5% level of significance. (16) ( Total / Jumlah: 20)