Statistical Testing of the Impact of Working Hours and High-Risk Work Conditions on Injury - Essay Example

? Statistical Testing of the Impact of Working Hours and High-Risk Work Conditions on Injury Rates Ali Ghandour Walden Quantitative Decision-Making for Business Analysis DDBA - 8438-1 Dr. Charlene Dunfee January 13, 2013 Statistical Testing of the Impact of Working Hours and High-Risk Work Conditions on Injury Rates The rate of injuries in the workplace is caused by a variety of factors including fatigue, and lack of protective measures, among others reasons. To reduce injuries in workplaces, organizations undertake different programs that include a set of common sense aspects that involve finding all possible hazards in the workplace and coming up with a plan for controlling and preventing those hazards (Kennedy, Amick, Dennerlein, Brewer, Catli, Williams, et al., 2010). Active work participation and good supervision are some of the important aspects in ensuring hazards are identified and tackled. Nevertheless, training workers is important so as to ensure that they are aware of ensuring safety in their workplaces. In this study, an investigation will be conducted in respect to the relationship between injury rates and different conditions in the workplaces. Although many organizations have some means of preventing and controlling hazards in workplaces, the effect of some conditions such as the total hours allocated for working and the impact of sensitization on high risk work places compared to less sensitization in low risk work places is ignored in many studies (Kennedy et al, 2010). Therefore, this study will investigate the impact that variation in the number of working hours and lack of protective sensitization in low risk workplaces, have on injury rates in workplaces. Research Questions 1. Is there any relationship between the time constraints (working hours) and the injury rates? 2. Is there any relationship between the degree of risk involved in working at a particular work place and the injury rates? 3. If there is a relationship between the factors mentioned above, what is the nature and significance of such a relationship? Setting up the Research Hypothesis Considering the research questions presented in the above section, following has been hypothesized in this research: For working hours and injury rates H0: Working hours is associated positively with the injury rates; H1: Working hours is associated negatively with the injury rates. For the degree of risk involved at workplace and injury rates H0: The degree of risk involved is positively associated with the injury rates; H1: The degree of risk involved is negatively associated with the injury rates; These tests of validity for these hypotheses on the basis of results and conclusions reached in the following sections enables the researcher to establish the relationship between identified variables in this research. Method and Results The number of actual hours worked by all employees in the area/team for the 12 month period ending December 31, 2009 were taken and recorded in an excel spreadsheets. Also, operations for supervisors differed in terms of activities and risks. Risk ranged from low (1) office related to high (7) manual material handling activities. Table 1 Risk Range 1 2 3 4 5 6 7 Low ? ? ? ? ? ? ? ? ? High This data was taken and recorded in an excel worksheet as well. Finally, the average rate of injuries per 100 employees over 12 month period was recorded on the excel worksheets. Among these variables, the injury rate was taken as the dependent variable while the level of risk and hours worked was taken as the independent variables. The aim of the study is to find out the relationship between injury rate on the one hand and hours worked and risk, on the other hand. In other words, the researcher formulated a statistical model to find out whether the risk and hours worked can be used to predict the rate of injuries in workplaces. The data collected in the excel worksheets are then imported into an SPSS sheet for statistical analysis. The analysis conducted under SPSS includes both descriptive analysis and regression analysis. The regression analysis shows the nature and significance of the relationship identified between the variables in this research work. It is pertinent to mention here that the three variables considered in this study include both dependent and independent variables: Hours Worked: Independent Variable Risk: Independent Variable Injury Rate: Dependent Variable Descriptive Findings Following are the descriptive statistics obtained through the analysis of information gathered by the researcher for three variables under consideration. Table 2 Descriptive Statistics N Minimum Maximum Mean Standard Deviation Hours Worked 51 10400.00 93600.00 49960.7843 15590.23590 Injury Rate 51 .00 76.92 15.1757 17.47468 Risk 51 1.00 7.00 4.5882 2.01173 The mean and standard deviation values for each of the three variables under consideration are presented in the table above. The values presented above show that there is a significant deviation in the hours worked and injury rates of the selected working environment. Findings from Regression Analysis Keeping in view the information available with regard to three variables under consideration, following regression analysis has been carried out: Table 3 Regression Analysis Model Summary Model R R Square Adjusted R Square Std. Error of the Estimate 1 .675a .455 .432 13.16423 a. Predictors: (Constant), Risk, Hours Worked ANOVA b Model Sum of Squares D f Mean Square F Sig. 1 Regression 6949.962 2 3474.981 20.052 .000a Residual 8318.256 48 173.297     Total 15268.217 50       a. Predictors: (Constant), Risk, Hours Worked b. Dependent Variable: Injury Rate Coefficients a Model Un standardized Coefficients Standardized Coefficients t Sig. B Std. Error Beta 1 (Constant) 55.650 6.654   8.363 .000 Hours Worked -.001 .000 -.552 -4.855 .000 Risk -2.080 .988 -.239 -2.105 .041 a. Dependent Variable: Injury Rate Following are the scatter plot diagrams which show the nature and significance of the relationship identified in the regression analysis. Figure 1 Scatter plot of Working Hours Vs Injury Rate Figure 1 Scatter plot of Risk Vs Injury Rate Discussion Keeping in view the findings obtained from regression analysis above, the coefficient of hours worked is -0.001 and that of the risk is -2.08. This means that the two independent variables are inversely related to the dependent variable. It also means that, when the hours worked and the level of risk is increased, the rate of injuries in the workplace is reduced (Morita, Lee & Mowday, 1993). The essence of this is twofold. First, when the workers are allocated adequate time to complete their tasks, there is a likelihood that they will concentrate and be more careful hence avoid injuries in the work places. Second, ideally, the workers that operate in high risk workplaces are in most cases sensitized on safety and protective measures, hence they are likely be become very careful when performing their work and thus avoid injuries. On the other hand, workers who operate in less risky environments such as the offices are rarely sensitized on safety measures and hence they are likely to be careless when performing their work, which contributes to the high level of injuries in such environments (Fallah & Mohammadzadeh, 2010). From the regression analysis, the adjusted R squared is 0.43, which means that this model is not very reliable in predicting injury rate considering that this ratio is quite far from 1. However, the p-values for both hours worked and risk is below 0.05, hence we reject the null hypothesis and conclude that more working hours and working in risky working environments have significant effect on the injury rate. Based on these findings, it can be stated in light of the research questions stated earlier that there is a negative relationship between working hours and injury rates and degree of risk involved in working environment and injury rate; and for the later set of variables, this relationship is significant. Test of Validity of Research Hypotheses Keeping in view the findings presented above, the research hypotheses established earlier can now be tested for their validity. For working hours and injury rates Since there is a negative relationship found between working hours and injury rates, therefore alternate hypotheses is accepted, which is, H1: Working hours is associated negatively with the injury rates. For the degree of risk involved at workplace and injury rates Since there is a negative relationship found between the degree of risk and injury rates, therefore alternate hypotheses is accepted, which is, H1: The degree of risk involved is negatively associated with the injury rates; Conclusion Based on the findings and discussion presented above and considering the test of validity for hypotheses established in this study, it can be concluded that, Working hours are negatively related to injury rates in a working environment; however, this relationship is not significant. Degree of risk involved in a working environment is negatively related to injury rates; and this relationship is significant in nature. Reference List Fallah, A., & Mohammadzadeh, M. (2010). Bayesian regression analysis with linked data using mixture normal distributions. Statistical Papers , 51 (2), 421-430. Kennedy, C. A., Amick, B. C., Dennerlein, J. T., Brewer, S., Catli, S., Williams, R., et al. (2010). Systematic review of the role of occupational health and safety interventions in the prevention of upper extremity musculoskeletal symptoms, signs, disorders, injuries, claims and lost time. Journal of Occupational Rehabilitation , 20 (2), 127-62. Morita, J. G., Lee, T. W., & Mowday, R. T. (1993). The regression-analog to survival analysis: A selected application to turnover research. Academy of Management Journal , 36 (6), 1430-1430. Read More