PhD Final Thesis April 2013.pdf - Anglia Ruskin Research Online

Thesis Keith Gale 20138.15 Interpretation of group statistics and independent samples t-testsAs described earlier in this chapter, Levene’s test for equality is used to determinewhether the same variance of scores occur for both groups. The results are subjectedto Eta squared value calculations with guidelines for interpretation provided byCohen (1998).8.15.1 Interpretation of variance between tender total and estimateEta squared for variance = -1.620²-1.620² + (60 + 60 – 2)Eta squared for variance = 0.022An independent t-test was used to compare the variance between tender total andestimates for discrete verses framework projects. There was no significant differencein scores for discrete projects (M=0.888, SD=0.097) and framework projects(M=0.858, SD=0.106), t (118) =-1.620, p=0.108). The magnitude of the differencesin the means was small (0.022).8.15.2 Interpretation of variance between lowest and accepted tenderEta squared for variance = -1.931²-1.931² + (60 + 60 – 2)Eta squared for variance = 0.031An independent t-test was used to compare the variance between lowest andaccepted tenders for discrete verses framework projects. There was no significantdifference in scores for discrete projects (M=1.000, SD=0.000) and frameworkprojects (M=1.003, SD=0.011), t (118) =-1931, p=0.056). The magnitude of thedifferences in the means was small (0.031).188