[問題] 一題看不懂的英文統計題

看板Statistics作者 (小鋒子)時間14年前 (2011/04/17 17:51), 編輯推噓0(006)
留言6則, 2人參與, 最新討論串1/1
女朋友的生統老師出了一題不知所云的考題 看了很久也看不懂,附上題目與解答 希望有神人幫幫忙解釋一下 A researcher wanted to study the effects of mentoring on intelligence scores. He wanted to know as a baseline what the average intelligence of his students were relative to the general population. He used a standardized IQ test which has a mean of 100 and standard deviation of 16. The 50 students in his study scored an average of 102 on the IQ test. At what percentile of intelligences is the average IQ of his students relative to his population ? 1. First find the standard error of the mean for a sample size of 50 ,16/SQRT(50) = 2.26 2. How many standard errors are there between the observed sample mean and the population mean: (102-100)/2.26 = .8849 standard errors. 3. The percent of area under the normal curve from negative infinity to .8849 =81.2%, meaning the average intelligence of this set of students is higher than 81.2% of all other samples of 50 students. It is also 31.2% above an average IQ given this sample size. Finally, we can use the 1-sample z-test to test hypotheses. The general framework of Hypothesis testing will be covered in future lessons. _____________________________________________________________________ 比較大的問題是我看不懂 At what percentile of intelligences is the average IQ of his students relative to his population ? 這句的意思看不太懂 解答中的第三點也看不出它想表達出的意思。81.2%的學生高於其他的學生? 這實在不懂阿 ※ 編輯: siaxing 來自: 114.27.134.195 (04/17 17:59)

04/17 18:51, , 1F
最後一句話是: 其學生的平均IQ相對於群體的百分位是多少?
04/17 18:51, 1F

04/17 18:52, , 2F
因為是算 "平均IQ", 所以在算百分位時是以樣本平均數的分布
04/17 18:52, 2F

04/17 18:53, , 3F
為計算依據.
04/17 18:53, 3F

04/17 18:54, , 4F
解答: 1. 計算出 Xbar 分布的標準差; 2. 計算出 Xbar 的 z值
04/17 18:54, 4F

04/17 18:54, , 5F
3. 計算出這個 Xbar 觀測值在其分布的百分位.
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04/17 22:32, , 6F
感謝,有比較了解一點
04/17 22:32, 6F
文章代碼(AID): #1DghWuF_ (Statistics)