QNT 351 FINAL EXAM NEW APRIL 2016
VERSION
QNT 351 FINAL EXAM
NEW APRIL 2016 VERSION
A time series trend equation for Hammer
Hardware is Y’ = 5.6 + 1.2t, where sales are in millions of dollars and t
increases by one unit for each year. If the value of sales in the base year of
2016 is $5.6 million, what would be the estimated sales amount for 2018?
$8
million
$6.8
million
Unable
to determine from given information
$5.6
million
A weight-loss company wants to statistically
prove that its methods work. They randomly selected 10 clients who had been on
the weight loss program for between 55 and 65 days. They looked at their
beginning weights and their current weight. The statistical test they should
utilize is:
t
test for difference in paired samples
z
test for two population proportions
z
test for two population means
t test
for two population means
QNT 351 FINAL EXAM NEW APRIL 2016 VERSION
An auditor for American Health Insurance
reports that 20% of policyholders submit a claim during the year. 15
policyholders are selected randomly. What is the probability that at least 3 of
them submitted a claim the previous year?
.200
.708
.250
.602
A research firm conducted a survey to
determine the mean amount steady smokers spend on cigarettes during a
week. A sample of 64 smokers revealed that = $20 and S =
$5. What is the 95% confidence interval for μ?
$18.78
to $21.23
18.16
to 21.84
$18.60
to $21.40
18.37
to 21.63
QNT 351 FINAL EXAM NEW APRIL 2016 VERSION
When a class interval is expressed as 100 up
to 200, _________________________.
Observations
with values of 200 are included in the class
Observations
with values of 200 are excluded from the class
Observations
with values of 100 are excluded from the class
The
class interval is 99
A group of women tried five brands of
fingernail polish and ranked them according to preference. What level of
measurement is this?
Ordinal
Nominal
Interval
Ratio
A coffee manufacturer is interested in whether
the mean daily consumption of regular-coffee drinkers is less than that of
decaffeinated-coffee drinkers. A random sample of 50
regular-coffee drinkers showed a mean of 4.35 cups per day, with a
standard deviation of 1.2 cups per day. A sample of 40 decaffeinated
coffee drinkers showed a mean of 5.84 cups per day, with a standard deviation
of 1.36 cups per day. What is your computed z-statistic?
z =
-2.45
z =
-5.44
z =
-1.81
z =
– 3.90
A hypothesis regarding the weight of newborn
infants at a community hospital is that the mean is 6.6 pounds. A sample of
seven infants is randomly selected and their weights at birth are recorded as
9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the alternate
hypothesis?
H1:
µ ≠ 6.6
H1:
µ ≥ 6.6
H1:
µ > 7.6
H1:
µ = 6.6
As the size of the sample increases, what
happens to the shape of the distribution of sample means?
It
approaches a normal distribution.
It
cannot be predicted in advance.
It
is positively skewed.
It
is negatively skewed.
You perform a hypothesis test at the .05 level
of significance. Your computed p-value turns out to .042. What is
your decision about the hypothesis?
You
would reject Ho
You
would accept Ho
You
would accept Ho if it is a two-tailed test, but reject Ho if a one-tailed test
You
can’t render a decision unless you know the computed test statistic
University officials say that at least 70% of
the voting student population supports a fee increase. If the 95% confidence
interval estimating the proportion of students supporting the fee increase is
[0.75, 0.85], what conclusion can be drawn?
Since
this was not based on the population, no conclusion can be drawn.
Seventy
percent is not in the interval, so assume it will not be supported.
The
interval estimate is above 70%, so infer that it will be supported.
Seventy
percent is not in the interval, so another sample is needed.
The mean of a normal distribution is 400
pounds. The standard deviation is 10 pounds. What is the probability of a
weight between 415 pounds and the mean of 400 pounds?
0.3413
0.5000
0.4332
0.1932
The MacBurger restaurant chain claims that the
waiting time of customers for service is normally distributed, with a mean of 3
minutes and a standard deviation of 1 minute. The quality-assurance
department found in a sample of 50 customers at the Warren Road MacBurger that
the mean waiting time was 2.75 minutes. When you perform a test of
hypothesis, what would be the resulting p-value?
.0586
.0384
.0471
.0512
The tread life of tires mounted on light-duty
trucks follows the normal probability distribution with a mean of 60,000 miles
and a standard deviation of 4,000 miles. Suppose you bought a set of four
tires, what is the likelihood the mean tire life of these four tires is between
57,000 and 63,000 miles?
1.00
Very
likely
0.4332
0.8664
In a distribution, the second quartile
corresponds with the __________.
Variance
Mode
Median
Mean
A group of 100 students was surveyed about
their interest in a new International Studies program. Interest was measured in
terms of high, medium, or low. In the study, 30 students responded high
interest, 40 students responded medium interest, and 30 students responded low
interest. What is the relative frequency of students with high interest?
.40
.30
.030
.50
The Director of Golf for a local course wants
to study the number of rounds played by members on weekdays. He gathered the
sample information shown below for 520 rounds. At the .05 significance
level, is there a difference in the number of rounds played by day of the
week?
Day
|
Rounds
|
Monday
|
124
|
Tuesday
|
74
|
Wednesday
|
104
|
Thursday
|
98
|
Friday
|
120
|
No,
because χ2 = 11.793
Yes,
because χ2 = 15.308
No,
because χ2 = 7.715
Yes,
because χ2 = 12.288
Which approach to probability assumes that the
events are equally likely?
Empirical
Mutually
exclusive
Classical
Subjective
Sales at a fast-food restaurant average $6000
per day. The restaurant decided to introduce an advertising campaign to
increase daily sales. To determine the effectiveness of the advertising
campaign, a sample of 49 days of sales was taken. It found that the average
daily sales were $6,400 per day. From past history, the restaurant knew that
its population standard deviation is about $1,000. The value of the test
statistic is _______.
1.96
6,000
6,400
2.8
A study by the National Park Service revealed
that 50% of the vacationers going to the Rocky Mountain region visit
Yellowstone Park, 40% visit the Grand Tetons, and 35% visit both. What is the
probability that a vacationer will visit at least one of these magnificent
attractions?
0.35
0.55
0.95
0.05
The ages of all the patients in the isolation
ward of the hospital are 38, 26, 13, 41, and 22. What is the population
standard deviation?
6.92
10.33
15.85
9.26
The distribution of a sample of the outside
diameters of PVC pipes approximates a symmetrical, bell-shaped distribution.
The arithmetic mean is 14.0 inches, and the standard deviation is 0.1 inches.
About 68% of the outside diameters lie between what two amounts?
13.5
and 14.5 inches
13.9
and 14.1 inches
13.0
and 15.0 inches
13.8
and 14.2 inches
Each month the National Association of
Purchasing Managers publishes the NAPM index. One of the questions asked
on the survey to purchasing agents is: Do you think that the economy is
expanding? Last month, of the 300 responses, 160 answered “yes” to the
question. This month, 170 of the 290 responses indicated that the economy
is expanding. If you’re testing to find if a larger proportion of agents
believe that the economy is expanding this month, what is your computed test
statistic?
z =
-1.29
t =
-1.25
t =
-1.07
z =
-1.11
The first card selected from a standard
52-card deck was a king. If it is returned to the deck, what is the probability
that a king will be drawn on the second selection?
1/3
or 0.33
1/13
or 0.077
1/4
or 0.25
12/13
or 0.923
What is the range of values for a coefficient
of correlation?
Unlimited
range
0
to +1.0
-1.0
to +1.0 inclusive
-3
to +3 inclusive
Consider the following regression analysis
between sales (Y in $1000) and social media advertising (X in
dollars). = 55,000 + 7X
The
regression equation implies that an:
increase
of $1 in advertising is associated with an increase of $7,000 in sales.
increase
of $1 in advertising is associated with an increase of $62,000 in sales.
increase
of $7 in advertising is associated with an increase of $7,000 in sales.
increase
of $1 in advertising is associated with an increase of $7 in sales.
When statisticians analyze sample data in
order to draw conclusions about the characteristics of a population, this is
referred to as:
Descriptive
statistics
Data
summarization
Statistical
inference
Data
analysis
What is the median of 26, 30, 24, 32, 32, 31,
27, and 29?
32
29.5
30
29
An example of a qualitative variable is
_________________.
Weight
of a person
Miles
between oil changes
Number
of children in a family
Color
of ink in a pen
Which
of the following is true regarding the normal distribution?
It has two modes.
The points of the curve meet
the x-axis at z = -3 and z = 3.
It is asymmetrical.
The mean, median, and mode are all
equal.
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