[考題] 95年測統兩題
請各位高手幫我看一下我到底哪裡算錯
如果有75人接受數學測驗,高 低分組(即整各測驗中得高分的前27%,
得低分的後27%) 各有18, 12人達對某一個題目
是問該題目的難度指數是多少?
我算:
Ph: 18/75=0.24 PL:12/75=0.16
P=0.24+0.16/2=0.2
答案給的是:0.75
該題目的鑑別度指數是多少
D=0.24-0.16=0.08
答案給的是0.30
感謝解答!!
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