Questions 9 to 11 are based on the conversation you have just heard.
A. To visit friends and give lessons.
B. To give concerts.
C. To play the violin for the Arts Festival.
D. To attend a wedding.
Questions 9 to 11 are based on the conversation you have just heard.
A. He always takes it with him.
B. It was made by his uncle.
C. He borrowed it from his uncle,
D. He got a free seat for it when traveling.
项目的区分度的计算方法之一是( )。
A. 鉴别指数，且常以测验总分代替
B. 将按所侧总分数的27％的比例分别抽选确定为高分组与低分组
C. 计算鉴别指数，D＞0，D越大，区分高低分组的程度越高
D. 计算鉴别指数，D＜0，D越大，区分高低分组的程度越低
平均差的优点有( )。
A. 平均差意义明确，计算容易
B. 较好地代表了数据分布的离散程度
C. 反应灵敏
D. 有利于进一步做统计分析
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