An industrial engineer conjectures that a major difference between successful and unsuccessful companies is the percentage of their manufactured products returned because of defectives In a study to evaluate this conjecture the engineer surveyed the quality control departments of 50 successful companies identified by the annual profit statement and 50 unsuccessful companies The companies in the study all produced products of a similar nature and cost The percentages of the total output returned by customers in the previous year are provided in following table Unsuccessful 11 35 Businesses 8 34 6 56 8 93 8 26 Successful Businesses 10 24 5 43 5 09 3 62 4 06 9 19 7 69 6 85 7 32 7 07 6 16 6 32 8 20 2 23 7 70 10 30 13 58 8 06 13 70 12 23 5 06 0 43 10 51 1 08 8 32 8 59 10 49 7 71 8 67 11 93 10 64 7 30 1 94 9 16 6 33 4 98 11 07 11 04 10 08 4 76 Unsuccessful Successful 6 77 0 47 9 82 6 07 3 83 6 82 6 98 11 69 8 53 13 81 10 13 10 82 6 69 7 51 4 96 6 03 9 77 9 40 9 14 11 41 4 59 9 34 0 91 4 46 9 05 The sample means and standard deviations are N Mean 50 8 97 50 5 72 11 15 9 36 10 00 9 02 6 44 1 38 2 39 6 17 2 13 6 41 9 38 8 39 5 45 6 70 9 50 8 81 11 06 0 17 2 41 0 27 8 32 7 98 9 67 5 66 8 99 1 97 4 19 7 47 7 24 8 48 St Dev 2 20 3 24 Let u mean percentage of their manufactured products returned because of defectives from unsuccessful