Answer Happy

(9.2) A supermarket chain is redesigning the checkout lanes and is considering two designs. The following summary shows information on customer checkout times at two stores where the two new systems have been installed. System A System B Sample size n2 =25 Sample mean X1 = 4.1 minutes x2 = 3.4 minutes Sample standard deviation S1 = 2.2 minutes S2 = 1.5 minutes na=22 Let uy be the true population mean checkout time of checkout lanes with System A uz be the true population mean checkout time of checkout lanes with System B The management of the supermarket chain is interested in testing whether the mean checkout times of the two systems significantly differ. a) (4 pts) Formulate the null and alternative hypotheses. b) (5 pts) State the appropriate test statistic and its distribut c) (6 pts) Compute the test statistic. d) (5 pts) At a = 0.05 level of significance, state your conclusion in the context of this study