Straighterline Introduction to Statistics
Correct 100%
Four steps in the process of statistics - ANSWER 1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
Categorical variable - ANSWER places individuals into one of several groups
Two types: nominal and ordinal
Quantitative Variable - ANSWER represents a measurement or a count
Two types: Interval and ratio
Nominal Variable - ANSWER categorical variables where there is no natural order
among the categories
Ordinal variable - ANSWER categorical variables where there is natural order among
the categories
Interval Variable - ANSWER a measurement or count for which it makes sense to talk
about the difference between values, but it does not make sense to talk about the ratio
between values; 0 does not represent the absence of quanitity
Ratio Variable - ANSWER quantitative variables for which it makes sense to talk about
the difference between values AND the ratio between values; 0 represents the absence
of quantity
What type of variable?:
eye color - ANSWER nominal
What type of variable?:
socioeconomic status with categories low, med, high - ANSWER Ordinal
What type of variable?:
Temperature - ANSWER Interval
What type of variable?:
Income - ANSWER Ratio
Visual display and numerical summary for a single categorical variable - ANSWER pie
chart or bar chart
and category percentages
, Visual display and numerical summary for a single quantitative variable - ANSWER
histogram or stemplot
and descriptive statistics
Association (does/does not) imply causation. - ANSWER Does not
Lurking Variable - ANSWER a variable that is not among the explanatory or response
variables in a study, but could substantially affect your interpretation of the relationship
among those variables
Simpson's paradox - ANSWER When a lurking variable causes you to rethink the
direction of an association
Probability sampling plan - ANSWER any sampling plan that relies on random selection
(avoids bias).
Simple Random Sampling - ANSWER Every member of the population has an equal
probability of being selected for the sample
Cluster Sampling - ANSWER Used when the population is naturally divided into groups.
Take a random sample of clusters and use all individuals within those clusters as the
sample.
Stratified sampling - ANSWER Used when the population is naturally divided into sub-
populations called stratum. Choose a simple random sample from each stratum and use
these together as the sample.
Multistage sampling - ANSWER a probability sampling technique involving at least two
stages: a random sample of clusters followed by a random sample of people within the
selected clusters
Observational study - ANSWER values of the variable or variables of interest are
recorded as they naturally occur; no interference
Sample surveys - ANSWER a particular type of observational study in which individuals
report variables' values themselves, frequently by giving their opinions.
Experiment - ANSWER researchers "take control" of the values of the explanatory
variable because they want to see how changes in the value of the explanatory variable
affect the response variable
The Complement Rule - ANSWER P(not A) = 1 - P(A)
useful for finding events of the type "at least one of..."
General Addition Rule - ANSWER P(A or B) = P(A) + P(B) - P(A and B)
Correct 100%
Four steps in the process of statistics - ANSWER 1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
Categorical variable - ANSWER places individuals into one of several groups
Two types: nominal and ordinal
Quantitative Variable - ANSWER represents a measurement or a count
Two types: Interval and ratio
Nominal Variable - ANSWER categorical variables where there is no natural order
among the categories
Ordinal variable - ANSWER categorical variables where there is natural order among
the categories
Interval Variable - ANSWER a measurement or count for which it makes sense to talk
about the difference between values, but it does not make sense to talk about the ratio
between values; 0 does not represent the absence of quanitity
Ratio Variable - ANSWER quantitative variables for which it makes sense to talk about
the difference between values AND the ratio between values; 0 represents the absence
of quantity
What type of variable?:
eye color - ANSWER nominal
What type of variable?:
socioeconomic status with categories low, med, high - ANSWER Ordinal
What type of variable?:
Temperature - ANSWER Interval
What type of variable?:
Income - ANSWER Ratio
Visual display and numerical summary for a single categorical variable - ANSWER pie
chart or bar chart
and category percentages
, Visual display and numerical summary for a single quantitative variable - ANSWER
histogram or stemplot
and descriptive statistics
Association (does/does not) imply causation. - ANSWER Does not
Lurking Variable - ANSWER a variable that is not among the explanatory or response
variables in a study, but could substantially affect your interpretation of the relationship
among those variables
Simpson's paradox - ANSWER When a lurking variable causes you to rethink the
direction of an association
Probability sampling plan - ANSWER any sampling plan that relies on random selection
(avoids bias).
Simple Random Sampling - ANSWER Every member of the population has an equal
probability of being selected for the sample
Cluster Sampling - ANSWER Used when the population is naturally divided into groups.
Take a random sample of clusters and use all individuals within those clusters as the
sample.
Stratified sampling - ANSWER Used when the population is naturally divided into sub-
populations called stratum. Choose a simple random sample from each stratum and use
these together as the sample.
Multistage sampling - ANSWER a probability sampling technique involving at least two
stages: a random sample of clusters followed by a random sample of people within the
selected clusters
Observational study - ANSWER values of the variable or variables of interest are
recorded as they naturally occur; no interference
Sample surveys - ANSWER a particular type of observational study in which individuals
report variables' values themselves, frequently by giving their opinions.
Experiment - ANSWER researchers "take control" of the values of the explanatory
variable because they want to see how changes in the value of the explanatory variable
affect the response variable
The Complement Rule - ANSWER P(not A) = 1 - P(A)
useful for finding events of the type "at least one of..."
General Addition Rule - ANSWER P(A or B) = P(A) + P(B) - P(A and B)
