Now a day's every second data is being generated rapidly through internet and hence for making proper decision has become a huge task. We are surrounded by data but starving for knowledge, to achieve more profits in business, knowledge plays a key role for decision makers. Data warehouse provides a feasible solution to manage data which should be elegant and accurate for proper analysis and decision making. The data which is collected from different sources may have dirty data, cleaning of data should be done before the data is loaded into warehouse in order to achieve quality data. Once the data have been cleaned it will produce precise results, when the data mining query is applied. Hence consistent data is essential and reliable for decision making. We proposed an algorithm which constructs a Decision for every attribute and Missing values are to be replaced with leaf Node values by which we can achieve more quality data on which mining techniques can be applied for a quality analysis.