A manager at a casual dining restaurant noted that 18​% of customers ordered soda with their meal. In an effort to increase soda​ sales, the restaurant begins offering free refills with every soda order for a​ two-week trial period. During this trial​ period, 21​% of customers ordered soda with their meal. To test if the promotion was successful in increasing soda​ orders, he manager wrote the following​ hypotheses: H0​: p=0.18 and Ha​: p=0.21​, where p represents the proportion of customers who ordered soda with their meal during promotion. Are these hypotheses written​ correctly? Correct any mistakes as needed.