A consumer group wants to estimate the proportion of university students
that have part-time jobs. Within the error of 4% with 95% confidence, how
large the sample size is required?
1068
1113
846
423
601
Jason claims that he can correctly identify whether a man is married or
single by the way he dresses. Suppose in actuality that if a man is married,
Jason can correctly identify the man as married 75% of the time. When a
man is single, Jason will incorrectly identify that man as married 20% of
the time. Presented with a man and asked to identify the marital status of
this man (who is either married or single), Jason considers this to be a
hypothesis test with the null hypothesis being that the man is married and
the alternative that the man is single. What would be a Type I error?
Saying that the man is married when in fact the man is married.
Saying that the man is married when in fact the man is single.
Saying that the man is single when in fact the man is single.
None of the above.
Which of the following is wrong for the normal distribution?
During the range of plus and minus one standard deviation around the
mean contains almost the probability of 0.5.
During the range of plus and minus two standard deviations around the
mean contains almost the probability of 0.95.
Its measures of central tendency (mean, median, and mode) are all
identical.
Its associated random variable has an infinite range (−∞ < X < ∞)
A normal distribution does not show as M-shape with two peaks.
The process is in a state of statistical control.
The returned items more than or less than the average returned item
value 6.46 shows not pattern. That is, the signaling shows no trend.
Although the sample size is not big, the owner is able to refer the data
to reduce the number of items that are returned for rework.
The peak happens on day 12 with 12 items returned. The incidence
happens occasionally. The manager should ignore it.
This is an control chart approach.
Referring to the output, what is the standard error of estimate?
2456.965
3.6854.48
265769.1
302623.5/16 = 18913.97
1.090553
Referring to the output, which of the following statement is false?
The normality or error assumption appears to be hold.
The errors appear to be random.
The homoscedasticity of error assumption appears to be hold.
There appears to be autocorrelation in the residuals.
The regression effect is statistically significant.
Degrees of freedom are (as “DF1, DF2, DF3” shown in the ANOVA Table)
6, 5, 30
5, 36, 41
5, 6, 36
5, 6, 36
5, 6, 30
Give the significance level of 0.01, which of the following is correct?
There is evidence of a difference among the students.
There is evidence of a difference among the internet advertisements.
The blocking has a significant effect in reducing the random error.
There is evidence of differences among students and among
advertisements.
There is no evidence of differences among students and among
advertisements.
假設10 個商品中有2 個有缺點,方法一由這10 個商品中隨機選取1 個,令X
為有缺點的商品個數,P(X)為其機率函數。方法一找出缺點的測試成本為500
元;方法二由這10 個商品中隨機選取4個,令Y為有缺點的商品個數,P(Y )為
其機率函數,方法二找出缺點的測試成本為1600 元。
列出X的機率分佈,即x 與f (x)。
假設10 個商品中有2 個有缺點,方法一由這10 個商品中隨機選取1 個,令X
為有缺點的商品個數,P(X)為其機率函數。方法一找出缺點的測試成本為500
元;方法二由這10 個商品中隨機選取4個,令Y為有缺點的商品個數,P(Y )為
其機率函數,方法二找出缺點的測試成本為1600 元。
列出Y的機率分佈,即y 與f (y)。
假設10 個商品中有2 個有缺點,方法一由這10 個商品中隨機選取1 個,令X
為有缺點的商品個數,P(X)為其機率函數。方法一找出缺點的測試成本為500
元;方法二由這10 個商品中隨機選取4個,令Y為有缺點的商品個數,P(Y )為
其機率函數,方法二找出缺點的測試成本為1600 元。
分別計算X 和Y 的期望值。
假設10 個商品中有2 個有缺點,方法一由這10 個商品中隨機選取1 個,令X
為有缺點的商品個數,P(X)為其機率函數。方法一找出缺點的測試成本為500
元;方法二由這10 個商品中隨機選取4個,令Y為有缺點的商品個數,P(Y )為
其機率函數,方法二找出缺點的測試成本為1600 元。
分別計算方法一和方法二找出一個缺點商品的平均測試成本。
令α = 2、β = 4。計算x = 0, 5, 10, 15, 20時f (x)的值。並以x 為橫軸,f (x)
為縱軸畫出X 的近似機率分佈。
計算α = 1、β = 4 條件下X的期望值。
假設一天24 小時中某一信箱收到的廣告信件個數和非廣告信件個數均為
Poisson 分佈,平均值分別為4 封與2 封。
試計算8 小時的工作時間中總共收到3 封信件的機率。
假設一天24 小時中某一信箱收到的廣告信件個數和非廣告信件個數均為
Poisson 分佈,平均值分別為4 封與2 封。
試計算在下班前一個小時內會收到1 封非廣告信件的機率。
當下列條件變化而其他條件不變的情況下,母體平均數信賴區間的估計會如何變
化?每小題均回答變大、變小、不變或沒有必然關係。
樣本數n 增加。
當下列條件變化而其他條件不變的情況下,母體平均數信賴區間的估計會如何變
化?每小題均回答變大、變小、不變或沒有必然關係。
信賴水準1 −α 提高。
當下列條件變化而其他條件不變的情況下,母體平均數信賴區間的估計會如何變
化?每小題均回答變大、變小、不變或沒有必然關係。
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