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comm 215: stats and shid > gyu assignment questions > Flashcards

gyu assignment questions Flashcards

1
Q

The number of standard deviations that a value x is from the mean is a(n) ____________.

a) z score
b) area
c) variance
d) exponential value

A

a) z score

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2
Q

The price-to-earnings ratio for firms in a given industry is distributed according to the normal distribution. In this industry, a firm with a standard normal variable value of z = 1

a) has a below average price-to-earnings ratio.
b) may have an above average or below average price-to-earnings ratio.
c) has an above average price-to-earnings ratio.
d) has an average price-to-earnings ratio.

A

c) has an above average price-to-earnings ratio.

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3
Q

A standard normal distribution has a mean of ____________ and standard deviation of ____________.

a) one, zero
b) zero, zero
c) zero, one
d) one, one

A

d) zero, one

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4
Q

In order to approximate the binomial distribution using the normal distribution, the following condition(s) must be met if p is near 1.

a) n can be as small as np > 5.
b) n > 5
c) np > 5 only
d) n must be larger than just meeting the condition of np > 5.

A

d) n must be larger than just meeting the condition of np > 5.

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5
Q

A property of continuous distributions is that

a) probabilities for continuous variables can be approximated using discrete random variables.
b) unlike discrete random variables, probabilities can be found using tables.
c) unlike discrete random variables, the probability that a continuous random variable equals a specific value is zero [P(X = x) = 0].
d) as with discrete random variables, the probability distribution can be approximated by a smooth curve.

A

c) unlike discrete random variables, the probability that a continuous random variable equals a specific value is zero [P(X = x) = 0].

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6
Q

Values of the standard normal random variable are measured

a) in squared units in which the mean is measured.
b) None of the choices is correct.

c) in the number of standard deviations from the mean.
with reference to specific units.

d) in the units in which the mean is measured.

A

b) None of the choices is correct.

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7
Q

According to data from the state blood program, 40 percent of all individuals have group A blood. Suppose that of six randomly selected individuals, three have group A blood. Would you believe the data from the state blood program?

a) Yes, probability is > .05.
b) Yes, probability is < .05.
c) No

A

a) Yes, probability is > .05.

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8
Q

One die is thrown. What is the expected value of the number of dots on the top face of the die?

a) 3.5
b) 3.0
c) 1.0
d) 4.0

A

a) 3.5

the expected value is the mean of random variable

A quantity equal to the average result of an experiment after a large number of trials

1(1/6) + 2(1/6) + 3(1/6) + 4(1/6) + 5(1/6) + 6(1/6)

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9
Q

Which of the following is a valid probability value for a discrete random variable?

a) −.7
b) .2
c) All of the choices are correct.
d) 1.01

A

b) .2

The probability of a discrete random variable can only be between 0 and +1.

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10
Q

Which one of the following statements is not an assumption of the binomial distribution?

a) The experiment consists of n identical trials.

b) Each trial results in one of two mutually exclusive
outcomes.

c) Sampling is with replacement.
d) Trials are independent of each other.
e) The probability of success remains constant from trial to trial.

A

c) Sampling is with replacement.

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11
Q

Which of the following statements about the binomial distribution is not correct?

a) The probability of success remains constant from trial to trial.
b) Trials are independent of each other.
c) Each trial results in a success or failure.
d) The experiment consists of n identical trials.
e) The random variable of interest is continuous.

A

e) The random variable of interest is continuous.

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12
Q

One die is thrown. What is the expected value of the number of dots on the top face of the die?

a) 3.5
b) 3.0
c) 1.0
d) 4.0

A

a) 3.5

expected value bhaye

1(1/6) + 2(1/6) + 3(1/6) + 4(1/6) + 5(1/6) + 6(1/6)

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13
Q

Which of the following is not a discrete random variable?

a) the number of defects in a sample selected from a population of 100 products
b) the number of criminals found in a five-mile radius of a neighborhood
c) the number of times a light changes red in a 10-minute cycle
d) the number of minutes required to run 1 mile

A

d) the number of minutes required to run 1 mile

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14
Q

If p = .5 and n = 4, then the corresponding binomial distribution is ____________.

a) right skewed
b) symmetric
c) left skewed
d) bimodal

A

b) symmetric

cause p = 0.5

q is also = 0.5

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15
Q

When p = .5, the binomial distribution will _________ be symmetric.

a) never
b) always
c) sometimes

A

b) always

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16
Q

If p = .1 and n = 5, then the corresponding binomial distribution is ____________.

a) right skewed
b) left skewed
c) symmetric
d) bimodal

A

a) right skewed

the closer the p is to 0, the more right skewed the binomial distribution is

if p is closer to 1, it is going to be left skewed

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17
Q

he binomial distribution is characterized by situations that are analogous to

a) drawing balls from an urn.
b) measuring the length of an item.
c) coin tossing.
d) counting defects on an item.

A

c) coin tossing

Binomial distributions assume a constant probability of success

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18
Q

A total of 50 raffle tickets are sold for a contest to win a car. If you purchase one ticket, what are your odds against winning?

a) 49 to 1
b) 50 to 1
c) 01
d) 05

A

a) 49 to 1

Probability of losing = 1 − probability of winning = 1 − 1/50 = 49/50.

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19
Q

The set of all possible outcomes for an experiment is called a(n) ____________.

a) event
b) probability
c) experiment
d) sample space

A

d) sample space

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20
Q

The probability model describing an experiment consists of

a) independent events.
b) sample space.
c) sample space and probabilities of the sample space outcomes.

d) probabilities of the sample space outcomes.
random variables.

e) random variables

A

c) sample space and probabilities of the sample space outcomes.

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21
Q

Consider a standard deck of 52 playing cards, a randomly selected card from the deck, and the following events: R = red, B = black, A = ace, N = nine, D = diamond, and C = club.
Are A and N mutually exclusive?

a) No, not mutually exclusive.
b) Yes, mutually exclusive.

A

b) Yes, mutually exclusive.

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22
Q

Determine whether these two events are mutually exclusive: voter who favors gun control and an unregistered voter.

a) not mutually exclusive
b) mutually exclusive

A

b) mutually exclusive

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23
Q

Consider a standard deck of 52 playing cards, a randomly selected card from the deck, and the following events: R = red, B = black, A = ace, N = nine, D = diamond, and C = club.
Are N and C mutually exclusive?

a) Yes, mutually exclusive.
b) No, not mutually exclusive.

A

b) No, not mutually exclusive.

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24
Q

A(n) _______________ probability is a probability assessment that is based on experience, intuitive judgment, or expertise.

a) objective
b) relative frequency
c) subjective
d) experimental

A

c) subjective

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25
Q

The _____________ of an event is a number that measures the likelihood that an event will occur when an experiment is carried out.

a) probability
b) outcome
c) observation
d) intersection

A

a) probability

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26
Q

Determine whether these two events are mutually exclusive: consumer with an unlisted phone number and a consumer who does not drive.

a) not mutually exclusive
b) mutually exclusive

A

a) not mutually exclusive

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27
Q

What is the probability of rolling a value higher than eight with a pair of fair dice?

a) 18/36
b) 10/36
c) 12/36
d) 8/36
e) 6/36

A

b) 10/36

Set up sample spaces: 36 total

10 have combination adding to more than 8

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28
Q

if two events are independent, we can _____________ their probabilities to determine the intersection probability.

a) multiply
b) add
c) divide
d) subtract

A

a) multiply

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29
Q

Consider a standard deck of 52 playing cards, a randomly selected card from the deck, and the following events: R = red, B = black, A = ace, N = nine, D = diamond, and C = club.
Are R and A mutually exclusive?

a) No, not mutually exclusive.
b) Yes, mutually exclusive.

A

a) No, not mutually exclusive.

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30
Q

Consider a standard deck of 52 playing cards, a randomly selected card from the deck, and the following events: R = red, B = black, A = ace, N = nine, D = diamond, and C = club.
Are R and C mutually exclusive?

a) No, not mutually exclusive.
b) Yes, mutually exclusive.

A

b) Yes, mutually exclusive.

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31
Q

A manager has just received the expense checks for six of her employees. She randomly distributes the checks to the six employees. What is the probability that exactly five of them will receive the correct checks (checks with the correct names)?

a) 1/3
b) 1/6
c) 1/2
d) 1
e) 0

A

e) 0

If five have received the correct check, then it follows that the sixth employee will receive the correct check. Thus, the probability that exactly five will receive the correct check is 0

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32
Q

The ___________ of two events A and B is the event that consists of the sample space outcomes belonging to both event A and event B.

a) complement
b) intersection
c) union
d) mutual exclusivity

A

b) intersection

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33
Q

What is the probability of rolling a seven with a pair of fair dice?

a) 8/36
b) 3/36
c) 6/36
d) 7/36
e) 1/36

A

c) 6/36

Set up sample spaces: 36 total

6 have combination adding to 6.

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34
Q

how many outcomes in a fair dice sample space?

A

36 outcomes in the sample space

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35
Q

Determine whether these two events are mutually exclusive: someone born in the United States and a US citizen.

a) not mutually exclusive
b) mutually exclusive

A

a) not mutually exclusive

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36
Q

Determine whether these two events are mutually exclusive: unmarried person and a person with an employed spouse.

a) mutually exclusive
b) not mutually exclusive

A

a) mutually exclusive

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37
Q

A coin is tossed 6 times. What is the probability that at least one head occurs?

a) 5/6
b) 1/2
c) 63/64
d) 1/64
e) 1/36

A

b) 1/2

38
Q

A pair of dice is thrown. What is the probability that one of the faces is a 3, given that the sum of the two faces is 9?

a) 1/3
b) 1/2
c) 1/36
d) 1/6
e) 1/4

A

b) 1/2

Set up sample spaces: 36 total

4 total to 9

2 of these have a three on the face

Given that there are 4 choices and 2 have a three, the probability is ½.

39
Q

The __________ of event X consists of all sample space outcomes that do not correspond to the occurrence of event X.

a) conditional probability
b) independence
c) dependence
d) complement

A

d) complement

40
Q

A(n) ______________ is a collection of sample space outcomes.

a) event
b) set
c) experiment
d) probability

A

a) event

41
Q

A ___________________ is a measure of the chance that an uncertain event will occur.

a) probability
b) population
c) sample space
d) random experiment
e) complement

A

a) probability

42
Q

A measurement located outside the upper limits of a box-and-whiskers display is ___________.

a) within the lower limits
b) always in the first quartile
c) an outlier
d) always the largest value in the data set

A

c) an outlier

43
Q

A quantity that measures the variation of a population or a sample relative to its mean is called the ____________.

a) variance
b) coefficient of variation
c) standard deviation
d) range
e) interquartile range

A

c) standard deviation

44
Q

The average of the squared deviations of the individual population measurement from the population mean is the ___________.

a) range
b) mean
c) median
d) standard deviation
e) variance

A

e) variance

45
Q

The point estimate of the _______________ is the positive square root of the sample variance.

a) population standard deviation
b) sample mean
c) range
d) sample standard variation
e) median

A

d) sample standard variation

46
Q

Another name for the 50th percentile is the ___________.

a) third quartile
b) median
c) mean
d) mode
e) first quartile

A

b) median

47
Q

A _____________ displays the frequency of each group with qualitative data and a _____________ displays the frequency of each group with quantitative data.

a) histogram, stem-and-leaf display
b) stem-and-leaf, pie chart
c) scatter plot, bar chart
d) bar chart, histogram

A

d) bar chart, histogram

48
Q

what displays the frequency of each group with qualitative data

A

bar chart

49
Q

what displays the frequency of each group with quantitative data

A

histogram

50
Q

A graphical portrayal of a quantitative data set that divides the data into classes and gives the frequency of each class is a(n) ___________.

a) ogive plot
b) dot plot
c) histogram
d) bar chart
e) Pareto chart

A

c) histogram

51
Q

When grouping a large sample of measurements into classes, the ______________ is a better tool than the ___________.

a) stem-and-leaf display, scatter plot
b) box plot, histogram
c) scatter plot, box plot
d) histogram, stem-and-leaf display

A

d) histogram, stem-and-leaf display

52
Q

A histogram that tails out toward smaller values is ___________.

a) skewed to the right
b) skewed to the left
c) a scatter plot
d) normal

A

b) skewed to the left

Smaller values are to the left of the center part of the graph, resulting in a tail to the left

Thus, the graph is skewed to the left

53
Q

A flaw possessed by a population or sample unit is ___________.

a) a defect
b) always random
c) the cause for extreme skewness to the right
d) displayed by a dot plot

A

a) a defect

By definition, a defect is a flaw in a population or sample element

54
Q

what is a defect

A

a flaw in a population or sample element

55
Q

The general term for a graphical display of categorical data made up of vertical or horizontal bars is called a(n) ___________.

a) ogive plot
b) pie chart
c) Pareto chart
d) bar chart

A

d) bar chart

56
Q

an ogive plot is based on what type of data?

A

based on quantitative data

57
Q

what is a specialized bar chart?

A

a Pareto chart is a specialized bar chart

58
Q

what is pie chart?

A

a pie chart is a circular graphical display

59
Q

An example of manipulating a graphical display to distort reality is ___________.

a) making the bars in a histogram equal widths
b) starting the axes at zero and stretching the axes
c) stretching the axes
d) starting the axes at zero

A

c) stretching the axes

60
Q

what is the appropriate method to do a graphical display?

A

Starting the axes at zero

61
Q

would it be okay to make a histogram of equal widths?

A

yeee boyyy

62
Q

As a general rule, when creating a stem-and-leaf display, there should be ______ stem values.

a) between 1 and 100
b) between 5 and 20
c) no fewer than 20
d) between 3 and 10

A

b) between 5 and 20

By definition, there should be between 5 and 20 stems to enable a reasonable display of the shape of the distribution

63
Q

A Stem-and-leaf display is best used to ___________.

a) display the shape of the distribution
b) provide a point estimate of the central tendency of the data set
c) provide a point estimate of the variability of the data set
d) None of the other choices is correct

A

a) display the shape of the distribution

It is more difficult to find central tendency and variability using a stem-and-leaf display

It is easy to visualize the shape of the distribution using stem-and-leaf.

64
Q

what is best use to display the shape of the distribution?

A

Stem-and-leaf display

65
Q

The change in the daily price of a stock is what type of variable?

a) ordinal
b) qualitative
c) random
d) quantitative

A

d) quantitative

Qualitative and ordinal have similar definitions

random variables are all characteristics of a population element

66
Q

true or false

Qualitative and ordinal have similar definitions

A

true

67
Q

A ratio variable has the following characteristic.

a) inherently defined zero value
b) meaningful order
c) predictable
d) categorical in nature

A

a) inherently defined zero value

By definition, ratio variables are quantitative and have an absolute zero value

68
Q

if we collect data on the number of wins each team in the NFL had during the 2011-12 season, we have _____________ data.

a) non-historical
b) survey
c) time series
d) cross-sectional

A

d) cross-sectional

A time series is a collection of data taken over time, while a cross-section is a collection of data taken at the same point in time.

69
Q

what is a time series?

A

a collection of data taken over time

70
Q

what is cross sectional data?

A

collection of data taken at the same point in time

71
Q

Which of the following is a quantitative variable?

a) a person’s gender
b) whether a person has a charge account
c) mileage of a car

dI the manufacturer of a cell phone

e) whether a person is a college graduate

A

c) mileage of a car

A quantitative variable is measurable and noncategorical

72
Q

If we collect data on the number of wins the Dallas Cowboys earned each of the past 10 years, we have _____________ data.

a) time series
b) non-historical
c) survey
d) cross-sectional

A

a) time series

A time series is a collection of data taken over time, while a cross-section is a collection of data taken at the same point in time

73
Q

Which of the following is a type of question used in survey research?

a) rating
b) dichotomous
c) free response
d) All of the other answers are correct

A

d) All of the other answers are correct

All three of the listed question types can be used in survey design

74
Q

When the data being studied are gathered from a published source, this is referred to as a(n) _______________.

a) observational data source
b) existing data source
c) cross-sectional data source
d) experimental data source

A

b) existing data source

75
Q

what is an experimental data source?

A

collection of data where one is able to manipulate values

76
Q

in observational data source, can the one gathering the data control the factors or values?

A

nah boy

77
Q

can cross sectional data be considered as a data source?

why or why not?

A

nah boy

it is a way of analyzing or displaying the data that has been collected

78
Q

Methods for obtaining a sample are called

a) probability sampling.
b) sampling designs.
c) random sampling.
d) sample surveys.

A

b) sampling designs.

79
Q

are probability and random sampling methods of obtaining a sample?

A

nah boy

80
Q

___________ refers to describing the important aspects of a set of measurements.

a) Cross-sectional analysis
b) Time series analysis
c) Runs plot
d) Descriptive statistics

A

d) Descriptive statistics

81
Q

Which of the following is a categorical variable?

a) daily sales in a store
b) value of company stock
c) air temperature
d) whether a person has a traffic violation
e) bank account balance

A

d) whether a person has a traffic violation

82
Q

a categorical variable is qualitative or quantitative?

A

qualitative

83
Q

A data set provides information about some group of individual _____________.

a) measurements
b) statistics
c) elements
d) variables

A

c) elements

84
Q

what do measurements do?

A

measurements assign values to a variable of an element

85
Q

what is statistics?

A

science of describing aspects of a set of measurements

86
Q

what are the characteristic elements of a population?

A

variables

87
Q

__________ consists of a set of concepts and techniques that are used to describe populations and samples.

a) Random sampling
b) Traditional statistics
c) Data mining
d) Time series analysis

A

b) Traditional statistics

88
Q

_____________ is the difference between a numerical description of the population and the corresponding descriptor of the sample.

a) Non-observation error
b) Non-response
c) Observation error
d) Sampling error

A

d) Sampling error

Non-response, non-observation and observation error occur during the survey process

Sampling error is a result of the survey process

89
Q

Data collected for a particular study are referred to as a data ____________.

a) set
b) variable
c) measurement
d) element

A

a) set

90
Q

what is an element

A

one unit of a population

91
Q

___________ sampling is where we know the chance that each element will be included in the sample, which allows us to make statistical inferences about the sample population.

a) Judgment
b) Voluntary
c) Probability
d) Convenience

A

c) Probability

92
Q

what type of sampling should definitely not be used to make valid statistical inferences about a population?

A

judgement sampling

voluntary sampling

convenience sampling

comm 215: stats and shid (15 decks)

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