Nancy Makso purchased a mailing list of 2,000 names and addresses for her
mail order business but after scanning the list she doubts the authenticity of the
list. She randomly selects five names from the list for validation. If 40% of the
names on the list are non-authentic, and x is the number of non-authentic
names in her sample, P(x = 0) is ________.
0.8154
0.0467
0.0778
0.4000
0.5000
A researcher wishes to determine the difference is two population means. To do
this, she randomly samples 9 items from each population and computes a 90%
confidence interval. The sample from the first population produces a mean of
780 with a standard deviation of 240. The sample from the second population
produces a mean of 890 with a standard deviation of 280. Assume that the
values are normally distributed in each population. The t value used for this
is ________.
1.860
1.734
1.746
1.337
2.342
A simple regression model developed for ten pairs of data resulted in a sum of
squares of error, SSE = 125 . The standard error of the estimate is ________.
12.5
3.5
15.6
3.95
25
Fernando Enders, a cost accountant at Ultimate Plastics, Inc. (UPI), is
analyzing the manufacturing costs of a molded plastic telephone handset
produced by UPI. Fernando's independent variable ( y ) is production lot size
(in 1,000's of units), and his dependent variable ( x ) is the total cost of the lot
(in $100's). Regression analysis of the data yielded the following tables.
− 0.73
0.73
0.28
− 0.28
0.00
Following the regression in question 4, using α = 0.05 , Fernando
should ________.
increase the sample size
suspend judgment
none of the predictor variables are significant at the 5% level
each predictor variable is significant at the 5% level
x1 is the only predictor variable significant at the 5% level
x2 is the only predictor variable significant at the 5% level
the intercept is not significant at 5% level.
Following question 6, the coefficient of multiple determination is ________.
0.0592
0.9138
0.1149
0.9559
1.0000
reject the null hypothesis and conclude the two variables are not
independent
reject the null hypothesis and conclude the two variables are independent
do not reject the null hypothesis and conclude the two variables are not
independent
do not reject the null hypothesis and conclude the two variables are
independent
do nothing
Morgan Dubai manages a portfolio of 200 common stocks. He classifies his
portfolio stocks by 'industry sector' and 'investment objective'.
Which of the following statements is true?
Growth and Healthcare are complementary events.
Electronics and Growth are independent.
Electronics and Growth are mutually exclusive.
Airlines and Healthcare are collectively exhaustive.
Electronics and Healthcare are collectively exhaustive.
The Wall Street Journal reported some interesting statistics on the job market.
One statistic is that 40% of all workers say they would change jobs for "slightly
higher pay". In addition, 88% of companies say that there is a shortage of
qualified job candidates. Suppose 16 workers are randomly selected and asked
if they would change jobs for "slightly higher pay". (15%)
(1) What is the probability that three, four, five, or six say yes? (5%)
(2) If 13 companies are contacted, what is the probability that exactly 10 say
there is a shortage of qualified job candidates? (5%)
(3) If 13 companies are contacted, what is the expected number of companies
that would say there is a shortage of qualified job candidates? (5%)
The hourly wages in a particular industry are normally distributed with mean
$13.20 and standard deviation $2.50. A company in this industry employs 40
workers, paying them an average of $12.20 per hour. Can this company be
accused of paying substandard wages? Use an α = 0.01 level test.
Nutritional information provided by Kentucky Fried Chicken (KFC) claims
that each small bag of potato wedges contains 4.8 ounces of food and 280
calories. A sample of ten orders from KFC restaurants in New York and New
Jersey averaged 358 calories. (20%)
(1) If the sample standard deviation was s = 54 , is there sufficient evidence to
indicate that the average number of calories in small bags of KFC potato
wedges is greater than advertised? Test at the 1% level of significance.
(5%)
(2) Construct a 99% lower confidence bound for the true mean number of
calories in small bags of KFC potato wedges. (5%)
(3) On the basis of the bound you obtained in part (2), what would you
conclude about the claim that the mean number of calories exceeds 280?
How does your conclusion here compare with your conclusion in part (1)
where you concluded a formal test of hypothesis? (10%)
Studies of the habits of white-tailed deer indicate that these deer live and feed
within very limited ranges, approximately 150 to 205 acres. To determine
whether the ranges of deer located in two different geographical areas differ,
researchers caught, tagged, and fitted 40 deer with small radio transmitters.
Several months later, the deer were tracked and identified, and the distance y
from the release point was recorded. The mean and standard deviation of the
distances from the release point were as given in the accompanying table.
(10%)
(1) If you have no preconceived reason for believing that one population mean
is larger than the other, what would you choose for your alterative
hypothesis? Your null hypothesis? Would your alterative hypothesis implies
a one-tailed or a two-tailed test? Explain. (5%)
(2) Do the data provide sufficient evidence to indicate that the mean distances
differ for the two geographical locations? Test using α = 0.10 . (5%)
An experimenter has prepared a drug dosage level that she claims will induce
sleep for 80% of people suffering from insomnia. After examining the dosage,
we feel that her claims regarding the effectiveness of the dosage are inflated. In
an attempt to disprove her claim, we administer her prescribed dosage to 20
insomniacs and we observe Y , the number for whom the drug dose induces
sleep. We wish to test the hypothesis 0 : 0.8 H p = versus the alternative,
Ha : p < 0.8 . Assume that the rejection region {y ≤ 12} is used. (10%)
(1) In terms of this problem, what is a type II error? (5 points)
(2) Find β when p = 0.6 . (5%)
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