This thesis aims to find and examine the factors that influence Type-1 error rates of the bootstrap, joint significance and Sobel test in between-subjects and within-subjects mediation designs....Show moreThis thesis aims to find and examine the factors that influence Type-1 error rates of the bootstrap, joint significance and Sobel test in between-subjects and within-subjects mediation designs. This is accomplished with the help of procedurally generated data in R. Sample size, amount of measurement error and the value of the non-zero mediation parameter of either a or b have a significant impact on the reported Type-1 error rates. The findings in the between-subjects design are not in accordance with previous findings and need further research. The findings in the within-subjects design, although not thoroughly researched, do comply with expectations.Show less