A child takes a handful of 3 cookies at random without replacement from a
jar of cookies containing 10 chocolate chip cookies, 6 vanilla wafers, and 4
sugar cookies. What is the probability that All 3 of the cookies picked by
the child are of the same type?
0.1053
0.1263
0.00006
0.0351.
Which of the following functions is NOT a probability density function
(pdf)?
Suppose that 43% of the U.S. Labor force consisted of women in 1980’s. Of
the women who worked, 7% held managerial positions, whereas 16% of
men who worked held such positions. Of all managers, what percentage
were women?
0.2481
0.0301
0.09
0.1213.
A cable TV franchise offers a month’s free viewing as an incentive to
customers to subscribe to a movie channel. Suppose that 60% of customers
will subscribe under this incentive activity. The franchise earns $50 for
each subscription. If 150 offers are provided, use the normal approximation
to estimate the probability that the revenue from these offers is greater
than $5,000. The answer is most close to:
0.0478
0.0567
0.0401
0.3906.
若欲研究朝陽科大學生每天睡眠時間,今隨機抽出100 個朝陽學生,調查結果如
下:(1)每天平均睡眠時間為5.7 小時、(2)標準差為2 小時、(3)有36%的學生每
天睡眠少於5 小時。下列敘述何者不正確?
5.7 小時與2 小時均是樣本統計量
36%是以下累積相對次數
母體是指朝陽科大的所有學生
樣本變異數是一固定常數值,即σ 2 = 22 = 4。
Which of the following distribution best describe the process of random
sampling?
Normal
Uniform
Exponential
Binomial
If a hypothesis test leads to the rejection of the null hypothesis
a Type I error is always committed.
a Type II error is always committed.
a Type I error may have been committed only.
Both Types of error may have been committed.
The Central Limit Theory describes the distribution of
X
σ 2
μ
Which of the following statement is not a correctly stated hypothesis
problem:
Two baseball teams, Bull and tiger, meet in a short playoff. The winner is
the first team to win 2 games. Define B and T as the event that team
Bull and Tiger, respectively, wins a game.
(A)List all possible outcomes of this playoff series. ________
(B)Suppose that the result of any games is statistically independent of the
results of all previous games, and that team Bull has probability 0.6 of
winning any particular game. What is the probability that the playoff
lasts 3 games? ________
(C)Given that the playoff lasts only 2 games, what is the probability that
team Bull wins the playoff? ________.
Suppose that X and Y are probabilistically independent random
variables, and that both X and Y have an exponential distribution with
parameter λ = 0.10 . Find P{X > 5.0 and Y > 5.0} = ________.
假設某種電池壽命為一常態分配,標準差為1.25 小時。今隨機抽取10 個電池測
試,此組樣本的平均壽命為40.5 小時。
(A)若欲用該組樣本檢定其母體平均數是否大於40 小時,則P 值為何?________
(B)今測試小組欲對母體平均數進行估計,若欲使對母體平均數的估計有95%的
信賴程度,其估計誤差小於0.4 小時,請問測試小組除了所抽取的10 個電池,
還需要再抽取多少個電池來測試?________
Of 1000 randomly selected cases of lung cancer, 823 resulted in death
within 10 years. Constructed a 95% one-sided upper confidence bound on
the death rate from lung cancer ________.
The height Y in inches of a randomly chosen male is a random variable
having a normal distribution with mean 70 inches and variance 4. (10%)
(A)What is the probability that a randomly chosen male will either be
smaller than 68 inches or taller than 75 inches? (5%)
(B)If we take a random sample of 10 males with replacement, what is the
probability that exactly 5 of these males will be 70 inches tall or taller? (5%)
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