[商管] 台大92商研統計
由於小弟手邊的解答是高點 但年份悠久 有些題目打錯 板上文章也少
詳解有些也跟我想的不同 因此想上來問問各位先進
92 台大商研統計題目 http://www.lib.ntu.edu.tw/exam/graduate/92/92411.pdf
16.Suppose a committee of 3 people is to be selected from a group consisiting
of 4 men and 5 women. What is the probability that all three people selected
are men? A)0.11 B)0.33 C)0.50 D)0.80
這題我算出來是0.04多 是不是題目有錯?
25.Let X1 and X2 be observations of a random sample from a distribution with
p.d.f. f(x)= 2x 0 < x < 1 , zero elsewhere. Evaluate the conditional
probability Pr( X1 < X2 | X1 < 2 X2).
A)3/8 B)8/17 C)4/7 D)3/11
這題我之前好像遇過 我算是1/4
但看解答還是不太了解為什麼分母的地方是先對x2積分
而不能上下分子分母都先對x1積分呢? 是不是範圍的定義問題?
39. In performing a regression analysis involving two numerical variables
(Y is dependent variable and X is independent variable), we are assuming
A) the variance of X and Y are equal
B) the variation around the line of regression is the same for each X value
C) that X and Y are independent
D) All of the above
我選A 答案是B 解答是說f(Y|X)的條件變異數相等 (?)
44. Which of the followings is correct?
A) the sample size in each independent sample must be the same if we are to
test for differences between the means of 2 independent populations
B) When we test for differences between the means of2 independent populations,
we can only use a two-tailed test
C) When testing for differences between the means of 2 related populations ,
we can use either a one-tailed or two-tailed test
D) The F distribution is symmetric.
我選B 答案是C 我選B是因為題目沒說是ANOVA 還是 t-test 所以我選B
煩請各位先進幫忙解惑 謝謝!! :)
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