D is the mean difference at which the power is computed. D = Mean1 - Mean2. Alpha is the probability of a false-positive result. Beta is the probability of a false-negative result. SD1 and SD2 are the standard deviations of groups 1 and 2, respectively. Summary Statements Group sample sizes of 78 and 78 achieve 80% power to detect non-inferiority using a one-sided, two-sample t-test. The margin of equivalence is -0.600. The true difference between the means is assumed to be 0.000. The significance level (alpha) of the test is 0.05000. The data are drawn from populations with standard deviations of 1.500 and 1.500. Statistical Analyses Statistical analyses will be conducted by using statistical software (SPSS 17.0). The proportions in 2 x2 contingency tables will be compared by the chi square test. The investigators will use a kappa statistic to evaluate for inter-observer and intra-observer variability in the bowel preparation quality. Multivariate analysis will be performed with multiple logistic regression to assess the impact of age and gender on bowel preparation. The investigators plan to have complete follow up of all patients and will use an intention to treat analysis.