A company wants to test clear deck sealants for weather resistance. Three brands of sealants will be tested using 60 pieces of d
ecking wood. The company wants to create treatment groups of 20 pieces of wood each, and decide to randomize using slips of paper. Select all the approaches that would result in comparable treatment groups. The numbers 1, 2, and 3 are each written on 20 slips of paper, and the slips are placed in a hat and shaken well. The top piece of wood from a stack is selected and a slip of paper is drawn from the hat. That piece of wood is assigned to the group number on the slip. The slip of paper is returned to the hat. This continues until all pieces of wood have been assigned to a group. The numbers 1, 2, and 3 are written on three slips of paper, put into a hat, and shaken well. A slip is drawn and the first 20 pieces of wood on the stack are assigned to the group number on the slip. Another slip is drawn and the next 20 pieces of wood are assigned to that group. The remaining pieces of wood are assigned to the remaining group. Each piece of decking wood is assigned a number from 1 to 60. The numbers 1–60 are written on slips of paper and placed in a hat and shaken well. Twenty slips are drawn, shaking the hat after each slip of paper is drawn, and the pieces of wood corresponding to those numbers are placed in group 1. Twenty more slips are drawn in the same way, and the pieces of wood corresponding to those numbers are placed in group 2. The pieces of wood corresponding to the numbers on the remaining slips are placed in group 3. The numbers 1, 2, and 3 are each written on 20 slips of paper (20 for each number) and the slips are placed in a hat and shaken well. The top piece of wood from a stack is selected, and a slip of paper is drawn from the hat. That piece of wood is assigned to the group number on the slip. The slip of paper is not returned to the hat. This continues until all pieces of wood have been assigned to a group.
