14.41 An investment company is going to make decision on which mobile app they are to invest from two different mobile application developments. The company accesses the ability on the two apps by monitoring the daily number of users downloading the apps for 20 days. The company ranked the daily downloading numbers from the lowest to the highest and found that first app has the sum of rank of 478. Test the null hypothesis for the company to determine if there is any difference between the two apps.