A large brokerage firm computed an arithmetic mean of 58.5 opening
transactions per day. The standard deviation is 15.8 and the median 63.5
opening transactions.
(1) Using Cheyshev’s theorem, in what percent of the days will there be
between 19.0 and 98.0 transactions. (c)
(2) What is the shape of transaction distribution? Symmetrical, positive
skewness (skew to right) or negative skewness (skew to left) The answer
and reason are (d) .
BB Electronics, Inc. purchases TV picture tubes from four different
suppliers. TW supplies 20 percent of the tubes, FI 30 percent, KP 25
percent, and Parts, Inc. 25 percent. TW tends to have the best quality, as
only 3 percent of their tubes arrive defective, FI tubes are 4 percent
defective, KP 7 percent, and Parts, Inc. 6.5 percent defective.
(1) What is the overall (average) percent defective? (e)
(2) A defective picture tube was discovered in the latest shipment. What is
the probability that it came from TW? (f)
The position of chief of police in a city of Taiwan is open. The search
committee, charged with the responsibility of recommending a new chief to
the city council, received 12 applications for the position. Four of the 12
applicants are female. The search committee decides to interview all 12 of
the applicants. The 4 randomly selected applicants are none of female.
What is the possibility of this occurrence? (g)
Suppose that your waiting time for a bus in the morning is uniformly
distributed on [0, 5], while waiting time in the evening is uniformly
distributed on [0, 10] independent of morning waiting time.
(1) If you take the bus each morning and evening for a week, what is your
total expected waiting time? (h)
(2) What is the variance of your total waiting time? (i)
A packaging experiment was conducted by placing two different package
designs for breakfast food side by side on a supermarket shelf. The
objective of the experiment was to see whether buyers indicated a
preference for one of the two package designs. In given day six customers
purchase a package from the supermarket, with one choosing package
design 1 and five choosing design 2.
(1) Let x be the number of buyers who choose the second package design.
What is the value of α for the test if the rejection region includes
x = 0 and x = 6 ? (l)
(2) What is the value of β for the alternative p = 0.8 (that is, 80% of the
buyers actually favor the second page design)? (m)
Past surveys revealed that 30 percent of the tourists going to Las Vegas to
gamble during a weekend spent more than $1,000. Management wants to
update that percentage. Using the .90 degree of confidence, management
wants to estimate the percentage of the tourists spending more than
$1,000 within 1 percent. What sample size should be employed? (n)
可觀看題目詳解,並提供模擬測驗!(免費會員無法觀看研究所試題解答)