# 幫幫忙~~~統計學問題樣本分配

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

2A survey was taken of 313 children,ages 14 to 22 years,from among the children of the nation\'s top corporate executives. When asked to identify the best aspect of being one of this privileged group,55% mentioned material and financial advantages. Suppose that the proportion p of children in the population is actually equal to 0.5. What is the probability of observing a sample proportion as large as or larger than the obsevred

^

value P=0.55?

3Twelve measurements were randomly selected from a normal population with mean

_

and standard deviation, 125.12 and 12.3, respectively. find P(X>130)?

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• 1 0 年前
最佳解答

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

1. 一個 100人的隨機樣本由母群體中被抽出, 它的平均數為10 , 變異數為9, 請找出

樣本平均數之抽樣分布的平均數和標準差, 同時也請找出樣本平均數小於 10.2

之機率為何?

2A survey was taken of 313 children,ages 14 to 22 years,from among the children of the nation's top corporate executives. When asked to identify the best aspect of being one of this privileged group,55% mentioned material and financial advantages. Suppose that the proportion p of children in the population is actually equal to 0.5. What is the probability of observing a sample proportion as large as or larger than the obsevred

value P=0.55?

2. 從全國的公司高階主管中的小孩裡, 我們針對 313 個小孩--年齡分別從 14到 22歲--進行調查, 當被問到請他們指出身為此一特殊團體的一分子最好的事情時, 55 % 提到了"物質跟財物上的優勢 ". 假如在母群體中孩童的比率 p 剛好等於 0.5 ,則

我們觀察到一個樣本比率等於或大於 p = 0.55的機率有多大?

3Twelve measurements were randomly selected from a normal population with mean

and standard deviation, 125.12 and 12.3, respectively. find P(X>130)? 3.

3. 12個測量結果由一個常態的母群體中被隨機抽出, 其平均數跟標準差分別為

125.12 和 12.3, 請問 P(x>130) =? <====應是問 x>130 的機率有多少?

加油吧!

2006-07-27 17:43:01 補充：

那第三題是問樣本平均數(X_bar)大於130的機率有多少? 自己要去查書本後面的表

參考資料： 自己, 統計愛好者
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• 1 0 年前

可是我不會算所以想請大大幫幫忙

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