Elementary Statistics Question 5 A quality control manager wants to check the quality of products in his textile factory by conducting a survey. On a certain day, the number of products produced is recorded as follows. Category Ties Suits Trousers Shirts Sweaters Number of items 300 450 600 750 300 It is required that 4% of the produced products should be selected for inspection. The following are two suggested methods for selecting the sample. Method I: Select items randomly from all produced products. Method II: Select items randomly from each category of clothing and the number of items selected from each category are in proportion to the number of items produced in that category. (a) Find the total sample size. (2 marks) (b) Write down the name of the sampling method for method I and method II respectively. (2 marks) (c) If Method II is used, find (i) the number of ties and (ii) the number of shirts in the sample. (2 marks) (d) What is the advantage of using Method II? (2 marks) (e) Referring to the following two variables, write down the type of the variable as discrete, continuous, or categorical. (ei) The length of a tie. (1 mark) (eli) The color of a tie. (1 mark) (Total: 10 marks)