13. A t-test A. Estimates the relationship between a dependent continuous variable and one or more continuous or categorical independent variables B. Estimates the relationship between two categorical variables C. Determines if there is a difference between the means of two groups, a categorical variable D. Determines if there is a difference between the means of two or more groups, a categorical variable 14. As sample size, n, increases the distance between the upper and lower control limits, UCLX and LCLX A. are unchanged B. decreases C. increases D. cannot be determined due to lack of relevant data 15. Rebasing of control limits should be undertaken A. when an organization implements a new system or processes B. every two years if not more frequently C. as performance is improved D. all of the above