The average score of the six math tests is a, and the average score of the last four times is 3 points higher than a. If the second time is 2 points more than the first time, how much is the average score of a (increase, decrease) in the last five times? (please specify "increased" or "decreased")
六次数学测验的平均分是a，后四次的平均分比a提高了3分，如果第二次比第一次多得2分，那么后五次平均分a(提高、降低)多少分(请指出"提高"还是"降低")
<result>1.4</result>