In a certain industrial process, an automatic grinding machine that produces the least surface roughness is to be selected. Four repeat test were run, using machines submitted by three different suppliers and the following data were obtained. Determine with 95% condence whether there is any significant difference between machines, and if so which one should be selected. Unstaked Data Grinding Machine A B C o g 21 12 15 U a 1.2 a 19 12 15 I: g 19 14 16 =4 21 13 18 Stacked Data Grinding Machine Surface Roughness A 21 A 19 A 19 A 21 B 12 B 12 B 14 B 13 C 15 C 15 C 16 C 18 1.1. Identify the treatment (factor) and the dependent variable (response) ln this situation, the 'Grinding Machines\" are the treatment and the \"Surface Roughness\" is considerd the response. 1.1.1 How many levels of the treatment (factor) do you use in this experiment? 3 since there are 3 diffrent suppliersl 1.1.2. How many replicates do you use in this experiment? 4 since surface toughness are done 4 times each 1.1.3. Comment on the degree of freedom values for each source of variation. How do you calculate them? Let number of levels of grinding machines : k : 3 Total number : n : 12 Degrees of freedom of treatment : kl : 2 Degrees in freedom of error : nk : 9 Degrees in freedom of total : nl : 11