ENGINEERING DATA ANALYSIS EXAM
QUESTIONS AND ANSWERS
NOMINAL SCALE - ANS-are both discrete and qualitative, however, numbers may be
assigned to the categories for the purpose of coding
CREATING A DATA MANAGEMENT PLAN - ANS-f you are collecting data from
people, you will likely need to anonymize and safeguard the data to prevent leaks of
sensitive information
Stratified Sampling - ANS-It is done by dividing population into subgroups and sample
each subgroup based on their strata. Once divided, each subgroup is randomly
sampled.
SAMPLESIZE - ANS-refers to the number of participants or observations included in a
study. This number is usually represented by n. The size of a sample influences two
statistical properties: 1) the precision of our estimates and 2) the power of the study to
draw conclusion
Descriptive statistics - ANS-Concerned with collection, organization and presentation of
data in a form understandable to all. This analysis summarize some of the importance
features of a set of data.
Inferential statistics - ANS-Concerned with the formulation of conclusions or
generalizations about a population based observation or a series of observations of a
sample drawn from the population. Simply known as, drawing of conclusions. In other
words, be able to draw logical conclusions from data, we usually make some
assumptions about the chances (or probabilities) of obtaining the different data values.
The totality of these assumptions is referred to as a probability model for the data
VARIABLE - ANS-is any characteristics whose value may change from one object to
another in the population. We shall initially denote variables by lowercase letters from
the end of our alphabet.
x =brand of calculator owned by students
y =number ofvisits to a particular Web
z = braking distance of an automobile under specified distance.
univariate - ANS-data set consists of observations on a single variable.
(MAAAMAAAMA)
, bivariate - ANS-data when observations are made on each of two variables. Example:
(Height,weight) (72, 168), (75, 212)
multivariate - ANS-data arises when observations are made on more than one variable
(so bivariate is a special case of multivariate).
QUALITATIVE VARIABLES. - ANS-Measures a quality or characteristics on each
experimental unit. The value of this variable depends on the characteristics of a subject
possess. Example: color, religion, sex and occupation
QUANTITATIVE VARIABLES - ANS-Indicates how much of that characteristic a subject
possess. These are often represented by numbers and can be meaningfully added,
subtracted, multiplied or divided. Example:
x-primeinterest
x-number ofpassengers on a flight from LA TO NY
x-weight of a package ready to be shipped
DISCRETE VARIABLES OR NON-CONTINUOUS VARIABLES - ANS-Take only
specific or isolated values along a scale. These are whole numbers, and are obtained
through the process of counting.
Example: number of times head appears after tossing a coin five times
CONTINUOUS VARIABLES. - ANS-Do not fall under the discreet category. This is
obtained by measuring, and can take on infinite number of values.
Examples of continuous variables are weight, height and temperature.
RANDOM VARIABLES - ANS-It is obtained by assigning a numerical value of each
outcome of a particular experiment.
is therefore a special kind of experiment in which the outcomes are numerical values,
either positive or negative or possibly zero.
is a real-valued function defined on a sample space. It is the main tool used for
modeling unknown quantities in statistical analysis.
DISCRETE DISTRIBUTION - ANS-Those that assign positive probability to at most
countably many different values. Example: Person's age. Consider an experiment in
which a person is selected at random from some population and his age is listed.
CONTINUOUS RANDOM VARIABLE - ANS-Example: Metal Cylinder Production A
company manufactures metal cylinders that are used in the construction of a particular
type of engine. These cylinders, which must slide freely within an outer casing, are
designed to have a diameter of 50mm. The company discovers, however, that the
cylinders it manufactures can have a diameter anywhere between 49.5 and 50.5mm.
Since this can take any value between 49.5 and 50.5, then it is a continuous random
variable.
QUESTIONS AND ANSWERS
NOMINAL SCALE - ANS-are both discrete and qualitative, however, numbers may be
assigned to the categories for the purpose of coding
CREATING A DATA MANAGEMENT PLAN - ANS-f you are collecting data from
people, you will likely need to anonymize and safeguard the data to prevent leaks of
sensitive information
Stratified Sampling - ANS-It is done by dividing population into subgroups and sample
each subgroup based on their strata. Once divided, each subgroup is randomly
sampled.
SAMPLESIZE - ANS-refers to the number of participants or observations included in a
study. This number is usually represented by n. The size of a sample influences two
statistical properties: 1) the precision of our estimates and 2) the power of the study to
draw conclusion
Descriptive statistics - ANS-Concerned with collection, organization and presentation of
data in a form understandable to all. This analysis summarize some of the importance
features of a set of data.
Inferential statistics - ANS-Concerned with the formulation of conclusions or
generalizations about a population based observation or a series of observations of a
sample drawn from the population. Simply known as, drawing of conclusions. In other
words, be able to draw logical conclusions from data, we usually make some
assumptions about the chances (or probabilities) of obtaining the different data values.
The totality of these assumptions is referred to as a probability model for the data
VARIABLE - ANS-is any characteristics whose value may change from one object to
another in the population. We shall initially denote variables by lowercase letters from
the end of our alphabet.
x =brand of calculator owned by students
y =number ofvisits to a particular Web
z = braking distance of an automobile under specified distance.
univariate - ANS-data set consists of observations on a single variable.
(MAAAMAAAMA)
, bivariate - ANS-data when observations are made on each of two variables. Example:
(Height,weight) (72, 168), (75, 212)
multivariate - ANS-data arises when observations are made on more than one variable
(so bivariate is a special case of multivariate).
QUALITATIVE VARIABLES. - ANS-Measures a quality or characteristics on each
experimental unit. The value of this variable depends on the characteristics of a subject
possess. Example: color, religion, sex and occupation
QUANTITATIVE VARIABLES - ANS-Indicates how much of that characteristic a subject
possess. These are often represented by numbers and can be meaningfully added,
subtracted, multiplied or divided. Example:
x-primeinterest
x-number ofpassengers on a flight from LA TO NY
x-weight of a package ready to be shipped
DISCRETE VARIABLES OR NON-CONTINUOUS VARIABLES - ANS-Take only
specific or isolated values along a scale. These are whole numbers, and are obtained
through the process of counting.
Example: number of times head appears after tossing a coin five times
CONTINUOUS VARIABLES. - ANS-Do not fall under the discreet category. This is
obtained by measuring, and can take on infinite number of values.
Examples of continuous variables are weight, height and temperature.
RANDOM VARIABLES - ANS-It is obtained by assigning a numerical value of each
outcome of a particular experiment.
is therefore a special kind of experiment in which the outcomes are numerical values,
either positive or negative or possibly zero.
is a real-valued function defined on a sample space. It is the main tool used for
modeling unknown quantities in statistical analysis.
DISCRETE DISTRIBUTION - ANS-Those that assign positive probability to at most
countably many different values. Example: Person's age. Consider an experiment in
which a person is selected at random from some population and his age is listed.
CONTINUOUS RANDOM VARIABLE - ANS-Example: Metal Cylinder Production A
company manufactures metal cylinders that are used in the construction of a particular
type of engine. These cylinders, which must slide freely within an outer casing, are
designed to have a diameter of 50mm. The company discovers, however, that the
cylinders it manufactures can have a diameter anywhere between 49.5 and 50.5mm.
Since this can take any value between 49.5 and 50.5, then it is a continuous random
variable.
