? 發問時間: 教育與參考考試 · 1 0 年前

請問一下統計題目(代PO~20點)~謝謝~!!!

今天我阿姨丟給我一份統計題目~說是他的作業~可是我是理工科的沒辦法幫他忙~所以我想麻煩各位一下~謝謝~!!!

1.A random sample of size 100were selected from a population with mean 10 and variance 9.Find the mean and standard deviation of the sampling distribution of the sample mean and also find the probability that sample mean is less than 10.2 ???

2. A survey was taken of 313 children,ages 14 to 22 years,from among the children

of the nation top execcutives.When asked to identify the best aspect of being are of

this privileged group,55% mentioned material and financial advantages.Suppose that the

proportion P of children in the porulation is actually cqual to 0.5 What is the probability of observing a sample proporion as large as or larger than the observed P=0.55???

3. Twelve neasurements were randomly selected from a normal population with mean and standard deviation,125.12 and 12.3,respectively.fond P(X>130)???

2 個解答

評分
  • Ted
    Lv 4
    1 0 年前
    最佳解答

    1.

    E(X_bar)=10

    SE=√(9/100)=0.3

    p(X_bar<10.2)=p(Z<(10.2-10)/0.3)=p(Z<0.67)=0.7486

    2.

    p(p>0.55)=p(Z>(0.55-0.5)/√(0.5*0.5/313))=p(Z>1.77)=0.0384

    3.

    p(x>130)=p(Z>(130-125.12)/12.3)=p(Z>0.4)=0.3446

  • 可以把ㄊ翻成中文ㄇ

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