1. Not Answered A scatter diagram shows the relationship
among which of the following?
The Correct
Answer: bivariate quantitative data
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2. Not Answered The Sanchez household is about to
install solar panels to reduce the cost of heating their house. In order to
know how much the solar panels help, they record their consumption of natural
gas before the panels are installed. The table below gives the data for 16
months. Heating degree-days are the usual measure of demand for heating. One
degree-day is accumulated for each degree a day’s average temperature falls
below 65 degrees. An average temperature of 20 degrees Fahrenheit, for example,
corresponds to 45 degree-days.
Month
Degree-days Gas (100 cu. ft.)
The Correct
Answer: amount of natural gas consumed
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3. Not Answered Refer back to question two. Make a scatter
diagram of the data set. What type of relation appears to exist between the two
variables?
The Correct
Answer: positive linear association
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4. Not Answered Refer back to question two. What is the
linear correlation coefficient, rounded to three decimal places?
The Correct
Answer: 0.995
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5. Not Answered Refer back to your result from question 4.
Based on the value of the linear correlation coefficient, what can be
concluded?
The Correct
Answer: There is almost a perfect positive linear association between the two
variables.
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6. Not Answered Refer back to question two. What is the
equation of the line that contains the points (13, 4.0) and (52, 11).
The Correct
Answer: y = 7/39x + 5/3
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7. Not Answered Refer back to question two. Find the
equation of the least-squares regression line.
The Correct
Answer: y = 0.19x + 1.09
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8. Not Answered Refer back to question seven. Based on the
equation of the least-squares regression line, predict the natural gas
consumption for 48 degree-days.
The Correct
Answer: 10.21
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9. Not Answered Refer back to question two. What are the
residuals for this data set, rounded to two decimal places?
The Correct
Answer: {0.67, 0.17, –0.32, 0.17, –0.70, 0.45, –0.15, 0.11, 0.11, –0.08, –0.12,
–0.26, –0.36, 0.06, 0.08, 0.14}
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10. Not Answered How does the fuel consumption of a car
change as its speed increases? Here are data for a British Ford Escort. Speed
is measured in kilometers per hour, and fuel consumption is measured in liter
of gasoline used per 100 kilometers traveled.
Speed (km/h)
Fuel Used (liters/100 km)
What is the
predictor variable?
The Correct
Answer: speed
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11. Not Answered Refer back to question ten. What is the
linear correlation coefficient, rounded to two decimal places?
The Correct
Answer: –0.17
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12. Not Answered Refer back to question eleven. Based on
the value of the linear correlation coefficient, what conclusion can you make?
The Correct
Answer: There is evidence of no linear relationship between the two variables.
--------------------------------------------------------------------------------
13. Not Answered Refer back to question ten. What is the
equation of the least-squares regression line?
The Correct
Answer: y = –0.01x + 11.06
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14. Not Answered Refer back to question thirteen. Based on
the equation of the least-squares regression line, predict the fuel consumption
for a speed of 78 km/h.
The Correct
Answer: 10.28
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15. Not Answered Refer back to question ten. What are the
residuals for this data set, rounded to two decimal places?
The Correct
Answer: {10.09, 2.24, –0.62, –2.47, –3.33, –4.28, –3.73, –2.94, –2.17, –1.32,
–0.42, 0.57, 1.64, 2.76, 3.97}
--------------------------------------------------------------------------------
16. Not Answered The Sanchez household is about to
install solar panels to reduce the cost of heating their house. In order to
know how much the solar panels help, they record their consumption of natural
gas before the panels are installed. The table below gives the data for 16
months. Heating degree-days are the usual measure of demand for heating. One
degree-day is accumulated for each degree a day’s average temperature falls
below 65 degrees. An average temperature of 20 degrees Fahrenheit, for example,
corresponds to 45 degree-days.
Month
Degree-days Gas (100 cu. ft.)
What is the
coefficient of determination, rounded to three decimal places?
The Correct
Answer: 0.991
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17. Not
Answered How does the fuel
consumption of a car change as its speed increases? Here are data for a British
Ford Escort. Speed is measured in kilometers per hour, and fuel consumption is
measured in liter of gasoline used per 100 kilometers traveled.
Speed (km/h)
Fuel Used (liters/100 km)
What is the
coefficient of determination, rounded to three decimal places?
The Correct
Answer: 0.029
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18. Not Answered Refer back to question two. The value
coefficient of determination can be interpreted in which of the following ways?
The Correct
Answer: Speed explains 2.9% of the variation in fuel consumption.
------------------------------------------------------------------------------
19. Not Answered How do you construct a residual plot?
The Correct
Answer: Plot the predictor variable along the horizontal axis and the residuals
along the vertical axis.
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20. Not Answered What criteria are necessary in a residual
plot in order for a linear model to be appropriate?
The Correct
Answer: both of the above
-------------------------------------------------------------------------------
21. Not Answered Refer back to question one. Is a linear
model appropriate for this data set?
The Correct
Answer: Yes
--------------------------------------------------------------------------------
22. Not Answered Refer back to question two. Is a linear
model appropriate for this data set?
The Correct
Answer: No, because a discernable pattern is visible.
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23. Not Answered In analyzing a scatter diagram, how do we
determine if outliers are present?
The Correct
Answer: both of the above
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24. Not Answered Which of the following represents an
observation that significantly affects the value of the slope and/or intercept?
The Correct
Answer: influential observation
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25. Not Answered Change the exponential expression, 1.23 =
m, to an equivalent expression involving a logarithm.
The Correct
Answer: 3 = log1.2m
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26. Not Answered Change the logarithmic expression, log35 =
c, to an equivalent expression involving an exponent.
The Correct
Answer: 3c = 5
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27. Not Answered Write the following expression as a sum of
logarithms. Express powers as factors.
logd (a3b7)
The Correct
Answer: 3logd a + 7logd b
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28. Not Answered Evaluate the following logarithmic
expression. Round your answer to three decimal places.
log 6.2
The Correct
Answer: 0.792
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29. Not Answered Beth is interested in finding a function
that explains the closing price of Dell Computer stock at the end of each
month. She obtains the following data:
Date Closing
Price
Using a
graphing utility, fit an exponential model to this data, rounded
to five decimal places. Let 1 represent November 1996, 2 represent December
1996, and so on.
The Correct
Answer: y = 6.27284(1.10426)x
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30. Not Answered Scott drops a ball from various heights
and records the time it takes for the ball to hit the ground. Using a motion
detector connected to his graphing calculator, he collects the following data:
Time t
(seconds) 1.528 2.015 3.852 4.154 4.625
Distance s
(meters) 11.46 19.99 72.41 84.45 104.23
Using a
graphing utility, fit a power model to this data, rounded
to three decimal places.
The Correct
Answer: y = 4.934x1.993
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1. Not Answered An experiment consists of rolling a die
once. If an odd number appears on the die, a coin is flipped once. If an even
number appears on the die, a coin is flipped twice. Which of the following
lists the elements of the sample space in this experiment, using “H” to denote
heads, and “T” to denote tails?
The Correct Answer: {1H, 1T,
2HH, 2HT, 2TT, 2TH, 3H, 3T, 4HH, 4HT, 4TT, 4TH, 5H, 5T, 6HH, 6HT, 6TT, 6TH}
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2. Not Answered An experimenter concludes that the more
times a die is rolled, the proportion of getting a four becomes closer and
closer to 1/6. What phenomenon is being described here?
The Correct Answer: The Law of
Large Numbers
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3. Not
Answered What approach is being used
if probabilities are approximated by dividing the number of times an event is
observed by the number of repetitions of the experiment?
The Correct Answer: The
Empirical Method
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4. Not Answered In a standard deck of 52 cards, what is
the probability of drawing a face card?
The Correct Answer: 3/13
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5. Not Answered Abby, Deborah, Sam, Tonya, and Roberto
work in a firm’s public relations office. Their employer must choose two of
them to attend a conference in
The Correct Answer: 10
-----------------------------------------------------------------------------
6. Not Answered Refer back to question five. What is the
probability of choosing Deborah and Sam?
The Correct Answer: 1/10
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7. Not Answered What is the probability that Tonya is
chosen?
The Correct Answer: 3/10
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8. Not Answered The following data represent the high
temperature distribution for the month of August in
Temperature Days
Approximate the probability, rounded to the nearest whole number, that a
randomly selected day in
The Correct Answer: 13%
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9. Not Answered Which of the following should be
interpreted with extreme caution?
The Correct Answer: subjective
probabilities
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10. Not Answered Select a first-year college student at
random and ask what his or her academic rank was in high school. Here are the
probabilities, based on proportions from a large sample survey of first-year
students:
What is the probability that a
randomly chosen first-year college student was not in the top 20% of his or her
high school class?
The Correct Answer: 0.59
-------------------------------------------------------------------------------
11. Not Answered Refer back to question ten. What is the
probability that a first-year student was in the top 40% in high school?
The Correct Answer: 0.64
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12. Not Answered Choose an acre of land in
The Correct Answer: 0.65
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13. Not Answered Refer back to question twelve. What is the
probability that the acre chosen is either forest of pasture?
The Correct Answer: 0.38
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14. Not Answered Refer back to question twelve. What is the
probability that a randomly chosen acre in
The Correct Answer: 0.62
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15. Not Answered Given the following events, which are
mutually exclusive?
A = {1, 2, 3, 4, 5}
B = { 5,
6, 7, 8, 9}
C = {0}
The Correct Answer: both of
the above
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16. Not Answered Which of the following are examples of
independent events?
The Correct Answer: weight and
IQ
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17. Not Answered A box contains the six letters, RANDOM.
What is the probability of the outcome DAN in that order if three letters are
drawn one by one with replacement?
The Correct Answer: 1/216
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18. Not Answered A
box contains the six letters, RANDOM. What is the probability of the outcome
DAN in that order if three letters are drawn one by one without replacement?
The Correct Answer: 1/120
-------------------------------------------------------------------------------
19. Not Answered There are two boxes that contain colored
and white balls. Box one contains 2 colored and 3 white balls.
What is the probability of two
white balls?
The Correct Answer: 1/5
-----------------------------------------------------------------------------
20. Not Answered Refer back to question four. What is the
probability of at least one colored ball?
The Correct Answer: 4/5
-------------------------------------------------------------------------------
21. Not Answered Refer back to question four. What is the
probability of at most one colored ball?
The Correct Answer: 11/15
-------------------------------------------------------------------------------
22. Not Answered Here are the counts (in thousands) of
earned degrees in the
Bachelor’s Masters Professional Doctorate
Total
What is the conditional
probability that you choose a woman, given that the person chosen received a
professional degree, rounded to three decimal places?
The Correct Answer: 0.4054
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23. Not Answered Carlin’s Pizza House offers 3 kinds of
salads, 15 kinds of pizza, and 4 kinds of desserts. How many different
three-course meals can be ordered?
The Correct Answer: 180
---------------------------------------------------------------------------
24. Not Answered If a coin is tossed five times, in how
many different ways can the sequence of heads and tails appear?
The Correct Answer: 32
----------------------------------------------------------------------------
25. Not Answered Sally has four red flags, three green
flags, and two white flags. How many nine-flag signals can she run up a
flagpole?
The Correct Answer: 1260
-----------------------------------------------------------------------------
26. Not Answered Assume a class has 30 members. In how many
ways can a president, vice-president, and a secretary be selected?
The Correct Answer: 24360
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27. Not Answered A five-volume numbered set of books is
placed randomly on a shelf. What is the probability that the books will be
numbered in the order from left to right?
The Correct Answer: 1/120
----------------------------------------------------------------------------
28. Not Answered Assume a club has 30 members. How many
committees of three people can be chosen?
The Correct Answer: 4060
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29. Not Answered How many different five-card hands can be
dealt from a standard deck of 52 playing cards?
The Correct Answer: 2598960
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30. Not Answered In a certain lottery game, 54 numbers are
randomly mixed and six are selected. A person must pick all six numbers to win.
Order is not important. What is the probability of winning?
The Correct Answer: 1/25827165
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1. Not Answered Which of the following random variables is
discrete?
The Correct Answer: The number
of 90 and higher degree-days in
--------------------------------------------------------------------------------
2. Not Answered Which of the following random variables is
continuous?
The Correct Answer: The time
it takes to drive from
--------------------------------------------------------------------------------
3. Not Answered Which of the following is a probability
distribution?
The Correct Answer: x P(X = x)
1 0.25 2 0.04
3 0.36 4 0.21 5 0.14
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4. Not Answered In the following probability distribution,
the random variable X represents the number of bad switches found by an
inspector.
x P(X = x) 0
0.35 1 0.38 2 0.2 3 0.05 4 0.02
Draw a probability histogram.
What is the shape of the distribution?
The Correct Answer: right
skewed
-------------------------------------------------------------------------------
5. Not Answered Refer back to question four. What is mean of the random variable X, rounded to two decimal
places?
The Correct Answer: 1.01
--------------------------------------------------------------------------------
6. Not Answered Refer back to question four. What is the
standard deviation of the random variable X, rounded to two decimal places?
The Correct Answer: 1.01
--------------------------------------------------------------------------------
7. Not Answered Refer back to question four. What is the
variance of the random variable X, rounded to two decimal places?
The Correct Answer: 1.02
-------------------------------------------------------------------------------
8. Not Answered Refer back to question four. What is the
probability that the inspector finds 2 bad switches?
The Correct Answer: 0.2
-------------------------------------------------------------------------------
9. Not Answered Refer back to question four. What is the
probability that the inspector finds 3 or 4 bad switches?
The Correct Answer: 0.07
-------------------------------------------------------------------------------
10. Not Answered Suppose it costs $8 to roll a pair of
dice. You get paid the sum of the numbers in dollars that appear on the dice.
What is the expected value of this game?
The Correct Answer: $7
------------------------------------------------------------------------------
11. Not Answered Refer back to question ten. Based on the
expected value, is this a fair game?
The Correct Answer: no
-------------------------------------------------------------------------------
12. Not Answered Determine which of the following
probability experiments qualify as a binomial experiment.
The Correct Answer: Fifty
students are taught about binomial distributions by a television program. After
completing their study, all students take the same examination. The number of
students who pass is counted.
-------------------------------------------------------------------------------
13. Not Answered Among employed women, 25% have never been
married. Select 10 employed women at random.
What is the probability that
exactly 2 of the 10 women in your sample have never been married?
The Correct Answer: 0.2816
------------------------------------------------------------------------------
14. Not Answered Refer back to question thirteen. What is
the probability that 2 or fewer have never been married?
The Correct Answer: 0.5256
-------------------------------------------------------------------------------
15. Not Answered Refer back to question thirteen. What is
the probability that more than 2 have never been married?
The Correct Answer: 0.4744
------------------------------------------------------------------------------
16. Not Answered Among employed women, 25% have never been
married. Select 10 employed women at random.
What is the probability that
at least 5 of them have never been married?
The Correct Answer: 0.0781
--------------------------------------------------------------------------------
17. Not Answered Refer back to question one. What is the
probability that no more than 6 of them have ever been married?
The Correct Answer: 0.9965
------------------------------------------------------------------------------
18. Not Answered One way of checking the effect of undercoverage, nonresponse, and
other sources of error in a sample survey is to compare the sample with known
facts about the population. About 12% of American Adults are black. The number
X of blacks in a random sample of 1500 adults should therefore vary with the
binomial (n = 1500, p = 0.12) distribution.
What is the mean of X?
The Correct Answer: 180
--------------------------------------------------------------------------------
19. Not Answered Refer back to question three. What is the
standard deviation of X?
The Correct Answer: 12.5857
------------------------------------------------------------------------------
20. Not Answered As the number of trials “n” in a binomial
experiment increase, the probability distribution of the random variable X
becomes which of the following?
The Correct Answer:
bell-shaped
------------------------------------------------------------------------------
21. Not Answered Refer back to questions three and four.
Using the answers for these questions and the Empirical Rule, which of the
following is an unusual result?
The Correct Answer: In a random
sample of 1500 adults, 210 are black.
-------------------------------------------------------------------------------
22. Not Answered How is the Poisson probability
distribution different from the binomial probability distribution?
The Correct Answer: The
Poisson probability distribution focuses on a specific interval (usually time
or space).
-------------------------------------------------------------------------------
23. Not Answered The mean number of business failures per
hour in the
Find the probability that
exactly 4 businesses will fail in any given hour.
The Correct Answer: 0.057
--------------------------------------------------------------------------------
24. Not Answered Refer back to question eight. Find the
probability that at least 4 businesses will fail in any given hour.
The Correct Answer: 0.9577
-------------------------------------------------------------------------------
25. Not Answered Refer back to question eight. Find the
probability that more than 4 businesses will fail in any given hour.
The Correct Answer: 0.9004
--------------------------------------------------------------------------------
26. Not Answered A newspaper finds that the mean number of
typographical errors per page is four. Find the probability that exactly three
typographical errors will be found on a page.
The Correct Answer: 0.1954
------------------------------------------------------------------------------
27. Not Answered Refer back to question eleven. Find the
probability that at most three typographical errors will be found on a page.
The Correct Answer: 0.4335
--------------------------------------------------------------------------------
28. Not Answered Refer back to question eleven. Find the
probability that more than three typographical errors will be found on a page.
The Correct Answer: 0.5665
----------------------------------------------------------------------------
29.
Not Answered At one point in a
recent year, the mean number of strokes per hole for golfer Tiger Woods was
about 3.9. Find the standard deviation.
The Correct Answer: 2.0
--------------------------------------------------------------------------------
30. Not Answered In
The Correct Answer: Poisson