The mean daily sales and customer satisfaction rate for two chain stores are as follow: Store A 10450 230 Store B 11523 175 Measure Mean (RM) Standard Deviation (RM) Number of days observation is made Satisfied customer (%) 45 45 85 82 i) Calculate 95% confidence interval of difference in sales between the stores.
ii) Based on the confidence interval calculated in part (1), determine if there is a significant difference in the mean sales between the stores. iii) Determine if the proportion of customers satisfied with the service provided by the store A is larger than store B at a = 0.05.