Statistics Introduction and Variables Q&A
Rated A+
Statistic - ✅✅ a number that represents a property of the sample
A number that summarizes the data collected from a sample
Representative sample - ✅✅ sample containing the characteristics of the
population
Variable {capital letters such as X and Y} - ✅✅ properties or characteristics of
some event, object, or person that can take on different values or amounts
Can be measured or counted
Constants - ✅✅ such as π that do not vary
Independent variable - ✅✅ a variable whose variation does not depend on that of
another that causes or influences another associated factor or phenomenon called a
dependent variable.
Manipulated by the experimenter
Dependent variable - ✅✅ A factor or phenomenon that is changed by the effect of
an associated factor or phenomenon called the independent variable.
Qualitative variables/categorical - ✅✅ express a qualitative attribute such as hair
color, eye color, religion, favorite movie, gender
Values of a qualitative variable do not imply a numerical ordering. Values of the
variable "religion" differ qualitatively; no ordering of religions is implied.
Categorical variables - ✅✅ another name for Qualitative variables
No natural sense of ordering. They are therefore measured on a nominal scale. Hair
color (Black, Brown, Gray, Red, Yellow) is a qualitative variable, as is name
(Adam, Becky, Christina, Dave . . .). Qualitative variables can be coded to appear
numeric but their numbers are meaningless, as in male=1, female=2
Nominal scale - ✅✅ is one of four Levels of Measurement. No ordering is
implied, and addition/subtraction and multiplication/division would be
inappropriate for a variable on a nominal scale. {Female, Male}Occasionally,
, numeric values are nominal: for instance, if a variable were coded as Female = 1,
Male = 2, the set {1,2} is still nominal
Statistics - ✅✅ the science dealing with the collection, analysis, interpretation,
and presentation of data
Descriptive Statistics - ✅✅ Organizing describing, and summarizing data
Do not involve generalizing beyond the data at hand
Inferential statistics - ✅✅ The formal methods used for drawing conclusions from
"good" data. Are called inferential statistics. Statistical inference uses probability
to determine how confident we can be that our conclusions are correct.
Data - ✅✅ 1. Information that has been collected from an experiment, a survey, a
historical record
2. Data are the actual values of the variable. They may be numbers or they may be
words
Quantitative data - ✅✅ are always numbers
Are the result of counting or measuring attributes of a population.
Quantitative discrete data - ✅✅ All data that are the result of counting
Quantitative continuous data - ✅✅ All data that are the result of measuring
Probability - ✅✅ the extent to which an event is likely to occur, measured by the
ratio of the favorable cases to the whole number of cases possible.
Population - ✅✅ the total "set" of observations that can be made
All elements, individuals, or units that meet the selection criteria for a group to be
studied, and from which a representative sample is taken for detailed examination.
Universe - ✅✅ The total of all populations
Sample - ✅✅ a set of data collected and/or selected from a statistical population
by a defined procedure.
The elements of a sample are known as sample points, sampling units or
observations
Sampling - ✅✅ select a subset
Rated A+
Statistic - ✅✅ a number that represents a property of the sample
A number that summarizes the data collected from a sample
Representative sample - ✅✅ sample containing the characteristics of the
population
Variable {capital letters such as X and Y} - ✅✅ properties or characteristics of
some event, object, or person that can take on different values or amounts
Can be measured or counted
Constants - ✅✅ such as π that do not vary
Independent variable - ✅✅ a variable whose variation does not depend on that of
another that causes or influences another associated factor or phenomenon called a
dependent variable.
Manipulated by the experimenter
Dependent variable - ✅✅ A factor or phenomenon that is changed by the effect of
an associated factor or phenomenon called the independent variable.
Qualitative variables/categorical - ✅✅ express a qualitative attribute such as hair
color, eye color, religion, favorite movie, gender
Values of a qualitative variable do not imply a numerical ordering. Values of the
variable "religion" differ qualitatively; no ordering of religions is implied.
Categorical variables - ✅✅ another name for Qualitative variables
No natural sense of ordering. They are therefore measured on a nominal scale. Hair
color (Black, Brown, Gray, Red, Yellow) is a qualitative variable, as is name
(Adam, Becky, Christina, Dave . . .). Qualitative variables can be coded to appear
numeric but their numbers are meaningless, as in male=1, female=2
Nominal scale - ✅✅ is one of four Levels of Measurement. No ordering is
implied, and addition/subtraction and multiplication/division would be
inappropriate for a variable on a nominal scale. {Female, Male}Occasionally,
, numeric values are nominal: for instance, if a variable were coded as Female = 1,
Male = 2, the set {1,2} is still nominal
Statistics - ✅✅ the science dealing with the collection, analysis, interpretation,
and presentation of data
Descriptive Statistics - ✅✅ Organizing describing, and summarizing data
Do not involve generalizing beyond the data at hand
Inferential statistics - ✅✅ The formal methods used for drawing conclusions from
"good" data. Are called inferential statistics. Statistical inference uses probability
to determine how confident we can be that our conclusions are correct.
Data - ✅✅ 1. Information that has been collected from an experiment, a survey, a
historical record
2. Data are the actual values of the variable. They may be numbers or they may be
words
Quantitative data - ✅✅ are always numbers
Are the result of counting or measuring attributes of a population.
Quantitative discrete data - ✅✅ All data that are the result of counting
Quantitative continuous data - ✅✅ All data that are the result of measuring
Probability - ✅✅ the extent to which an event is likely to occur, measured by the
ratio of the favorable cases to the whole number of cases possible.
Population - ✅✅ the total "set" of observations that can be made
All elements, individuals, or units that meet the selection criteria for a group to be
studied, and from which a representative sample is taken for detailed examination.
Universe - ✅✅ The total of all populations
Sample - ✅✅ a set of data collected and/or selected from a statistical population
by a defined procedure.
The elements of a sample are known as sample points, sampling units or
observations
Sampling - ✅✅ select a subset
