Rugby Injuries The prevalenceand patterns of knee injuries

Chapter 14, Problem 57

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Rugby Injuries The prevalenceand patterns of knee injuries among womencollegiate rugby players were investigated using asample questionnaire, to which 42 rugby clubsresponded.20 A total of 76 knee injuries were classifiedby type as well as the position (forward or back)of the player.Type of Knee InjuryMeniscal MCL ACL Patella PCLPosition Tear Tear Tear Dislocation TearForward 13 14 7 3 1Back 12 9 14 2 1 Chi-Square Test: Men Tear, MCL Tear, ACL Tear,Patella, PCL TearExpected counts are printed below observed countsChi-Square contributions are printed below expectedcounts Men Tear MCL Tear ACL Tear Patella PCL Tear Total 1 13 14 7 3 1 38 12.50 11.50 10.50 2.50 1.00 0.020 0.543 1.167 0.100 0.000 2 12 9 14 2 1 38 12.50 11.50 10.50 2.50 1.00 0.020 0.543 1.167 0.100 0.000Total 25 23 21 5 2 76Chi-Sq = 3.660, DF = 4, P-Value = 0.4544 cells with expected counts less than 5.0 a. Use the MINITAB printout to determine whetherthere is a difference in the distribution of injurytypes for rugby backs and forwards. Have any ofthe assumptions necessary for the chi-square testbeen violated? What effect will this have on themagnitude of the test statistic?b. The investigators report a significant differencein the proportion of MCL tears for the two positions(P .05) and a significant difference in theproportion of ACL tears (P .05), but indicatethat all other injuries occur with equal frequencyfor the two positions. Do you agree with thoseconclusions? Explain.