A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results: #1 15 Machine Obs. 17 15 #2 16 25 18 #3 23 24 23 Use the factor table to answer the following questions. 17 25 22 Size of Sample in 2 Factor for UCL and LCL for 2-Chart (4) 1.890 Factor for LCL for R-Chart (0) 0 Factor for UCL for R-Chart (D) 3.267 3 1.023 0 2.575 4 0.729 0 2.282 5 0.577 0 2.115 6 0.483 0 2.004 7 0.419 0.076 1.924 8 0.373 0.136 1.864 9 0.337 0.184 1.816 10 0.308 0.223 1.777 Source: Reprinted with permission from ASTM Manual on Ouality Control of Materials, copyright ASTM International, 100 Bar Harbor Drive, West Conshohodken, PA 19428 Question 24 (3.3 points) Listen What is the mean of sample means? (Answer in a whole number.) Question 25 (3.3 points) Listen What is the average of sample ranges? (Answer with two decimal point.) A/ Question 26 (3.3 points) Listen Compute the lower control limit for the x-bar chart (round your answer to two decimal points.) A/ Question 27 (2.15 points) Listen Which machine(s), if any, appear(s) to have an out-of-control process mean? machine #3 none of the machines machine #2 all of the machines machine #1