What are the advantages and disadvantages of transforming continuous
measurements into either discrete or ordinal ones?
What are the three underlying assumptions associated with the binomial
distribution?
Explain the usefulness of the central limit theorem in words.
The lifetime of an electronic device is a random variable which follows an
exponential probability with a mean of 50 hours. What is the probability
that the device will fail in the first 25 hours of operation?
0.56
0.394
0.25
0.84
The mean tuition cost at state universities throughout the United States is
$4260 per year. Use this value as the population mean and assume that
the population standard deviation is $900. Suppose that a random sample
of 50 state universities will be selected. What is the probability that the
simple random sample will provide a sample mean within $100 of the
population mean?
0.3
0.73
0.57
0.25
Given two random variables, X and Y , with E(X) = 2 , E(Y ) = 1 ,
Var(X) = 6 , Var(Y ) = 3 , E(XY ) = 5 , then Cov(2X + 3Y, X − 2Y ) =
12
4
-5
-9
According to Nielsen Media Research, kids aged 12 to 17 watched an
average of 3 hours of the television per day for the broadcast year that
ended in August. Suppose that the standard deviation is 1 hour and that
the distribution of the time spent watching television has a bell-shaped
distribution.
(a) What percentage of kids aged 12 to 17 watches television between 2 and
3 hours per day?
(b) What percentage of kids aged 12 to 17 watches television between 1 and
4 hours per day?
( Z ~ N(0,1) ; P(Z < −2.0128) = 0.0239 ; P(Z < 1.645) = 0.95 ; P(Z < −2.0128) = 0.0239 ; P(Z < −1.5) = 0.067 )
In December 1997, the U.S. Department of Justice issued an injunction (法
院的禁止令) against Microsoft Cooperation for bundling its Internet
Explorer Web browser with its Windows 95 operation system. Public
opinion was divided on whether Microsoft was a monopoly (壟斷). In a
Fortune poll, 41% of respondents agreed with the statement, “Microsoft is
a monopoly.”
(a) For a sample of 800 people, how many people would you expect to agree
that Microsoft is a monopoly?
(b) For a sample of 800 people, what is the probability that 300 or fewer
agree that Microsoft is a monopoly?
請問受訪選民是否對於兩位候選人之喜好有顯著差異?試以一般假設檢定,區間估
計及p-值法討論之。何謂信心?
A market research firm is interested in the possible success of new flavors of
ice cream. A study was conducted with three different flavors-- peach,
almond, and coconut. Three participants were given a sample of each ice
cream, in random order, and asked to rate the flavors on a 100-point scale.
The results are given in the table below.
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