Straighterline Introduction to Statistics Exam Questions
and Answers
Four steps in the process of statistics - ans -1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
Categorical variable - ans -places individuals into one of several groups
Two types: nominal and ordinal
Quantitative Variable - ans -represents a measurement or a count
Two types: Interval and ratio
Nominal Variable - ans -categorical variables where there is no natural order
among the categories
Ordinal variable - ans -categorical variables where there is natural order among
the categories
Interval Variable - ans -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 - ans -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 - ans -nominal
What type of variable?:
socioeconomic status with categories low, med, high - ans -Ordinal
What type of variable?:
Temperature - ans -Interval
, Interpreting Scatterplots:
How to tell if a linear relationship is strong or weak - ans -closer to -1 is a strong
negative linear relationship
closer to +1 is a strong positive linear relationship
close to 0 is a weak linear relationship
Interpreting Scatterplots:
Linear regression - ans -Finding the line that best fits the pattern of the linear
relationship (the line that describes how the response variable linearly depends
on the explanatory variable
Interpreting Scatterplots:
Least Squares Regression Line - ans -Has the smallest sum of squared vertical
deviations of the data points from the line.
Interpreting Scatterplots:
Extrapolation - ans -Prediction for ranges of the explanatory variable that are not
in the data; is not reliable and should be avoided
Association (does/does not) imply causation. - ans -Does not
Lurking Variable - ans -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 - ans -When a lurking variable causes you to rethink the
direction of an association
Probability sampling plan - ans -any sampling plan that relies on random selection
(avoids bias).
Simple Random Sampling - ans -Every member of the population has an equal
probability of being selected for the sample
and Answers
Four steps in the process of statistics - ans -1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
Categorical variable - ans -places individuals into one of several groups
Two types: nominal and ordinal
Quantitative Variable - ans -represents a measurement or a count
Two types: Interval and ratio
Nominal Variable - ans -categorical variables where there is no natural order
among the categories
Ordinal variable - ans -categorical variables where there is natural order among
the categories
Interval Variable - ans -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 - ans -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 - ans -nominal
What type of variable?:
socioeconomic status with categories low, med, high - ans -Ordinal
What type of variable?:
Temperature - ans -Interval
, Interpreting Scatterplots:
How to tell if a linear relationship is strong or weak - ans -closer to -1 is a strong
negative linear relationship
closer to +1 is a strong positive linear relationship
close to 0 is a weak linear relationship
Interpreting Scatterplots:
Linear regression - ans -Finding the line that best fits the pattern of the linear
relationship (the line that describes how the response variable linearly depends
on the explanatory variable
Interpreting Scatterplots:
Least Squares Regression Line - ans -Has the smallest sum of squared vertical
deviations of the data points from the line.
Interpreting Scatterplots:
Extrapolation - ans -Prediction for ranges of the explanatory variable that are not
in the data; is not reliable and should be avoided
Association (does/does not) imply causation. - ans -Does not
Lurking Variable - ans -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 - ans -When a lurking variable causes you to rethink the
direction of an association
Probability sampling plan - ans -any sampling plan that relies on random selection
(avoids bias).
Simple Random Sampling - ans -Every member of the population has an equal
probability of being selected for the sample
