STRAIGHTERLINE INTRODUCTION TO
STATISTICS EXAM QUESTIONS &
ANSWERS
Four steps in the process of statistics - Correct Answers -1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
Categorical variable - Correct Answers -places individuals into one of several groups
Two types: nominal and ordinal
Quantitative Variable - Correct Answers -represents a measurement or a count
Two types: Interval and ratio
Nominal Variable - Correct Answers -categorical variables where there is no natural
order among the categories
Ordinal variable - Correct Answers -categorical variables where there is natural order
among the categories
Interval Variable - Correct Answers -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 - Correct Answers -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 - Correct Answers -nominal
What type of variable?:
socioeconomic status with categories low, med, high - Correct Answers -Ordinal
What type of variable?:
Temperature - Correct Answers -Interval
, What type of variable?:
Income - Correct Answers -Ratio
Visual display and numerical summary for a single categorical variable - Correct
Answers -pie chart or bar chart
and category percentages
Visual display and numerical summary for a single quantitative variable - Correct
Answers -histogram or stemplot
and descriptive statistics
Visual display and numerical summary for C->C - Correct Answers -Two way table and
conditional percentages
Visual display and numerical summary for C->Q - Correct Answers -Side by side box
plots and descriptive statistics
Visual display and numerical summary for Q->Q - Correct Answers -Scatterplot and
correlation coefficient (r)
Standard Deviation Rule - Correct Answers -Approximately
68% of observations fall within 1 sd of the mean,
95% within 2 sd,
99.7% (or virtually all) within 3 sds
Interquartile Range (IQR) - Correct Answers -Middle 50% of the data
IQR= Q3-Q1
Finding an outlier using IQR - Correct Answers -An observation is considered a
suspected outlier if it is:
less than Q1 - 1.5(IQR), or
more than Q3 + 1.5(IQR).
Interpreting scatterplots:
1. positive relationship displays as
2. negative relationship displays as - Correct Answers -1. upward slope
2. downward slope
Interpreting Scatterplots:
How to tell if a linear relationship is strong or weak - Correct Answers -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:
STATISTICS EXAM QUESTIONS &
ANSWERS
Four steps in the process of statistics - Correct Answers -1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
Categorical variable - Correct Answers -places individuals into one of several groups
Two types: nominal and ordinal
Quantitative Variable - Correct Answers -represents a measurement or a count
Two types: Interval and ratio
Nominal Variable - Correct Answers -categorical variables where there is no natural
order among the categories
Ordinal variable - Correct Answers -categorical variables where there is natural order
among the categories
Interval Variable - Correct Answers -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 - Correct Answers -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 - Correct Answers -nominal
What type of variable?:
socioeconomic status with categories low, med, high - Correct Answers -Ordinal
What type of variable?:
Temperature - Correct Answers -Interval
, What type of variable?:
Income - Correct Answers -Ratio
Visual display and numerical summary for a single categorical variable - Correct
Answers -pie chart or bar chart
and category percentages
Visual display and numerical summary for a single quantitative variable - Correct
Answers -histogram or stemplot
and descriptive statistics
Visual display and numerical summary for C->C - Correct Answers -Two way table and
conditional percentages
Visual display and numerical summary for C->Q - Correct Answers -Side by side box
plots and descriptive statistics
Visual display and numerical summary for Q->Q - Correct Answers -Scatterplot and
correlation coefficient (r)
Standard Deviation Rule - Correct Answers -Approximately
68% of observations fall within 1 sd of the mean,
95% within 2 sd,
99.7% (or virtually all) within 3 sds
Interquartile Range (IQR) - Correct Answers -Middle 50% of the data
IQR= Q3-Q1
Finding an outlier using IQR - Correct Answers -An observation is considered a
suspected outlier if it is:
less than Q1 - 1.5(IQR), or
more than Q3 + 1.5(IQR).
Interpreting scatterplots:
1. positive relationship displays as
2. negative relationship displays as - Correct Answers -1. upward slope
2. downward slope
Interpreting Scatterplots:
How to tell if a linear relationship is strong or weak - Correct Answers -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:
