StraighterLine Introduction to Statistics MOST
RECENT EXAM UPDATED ACTUAL Exam Question
and Answer (2026/2027) | Detailed Rationales
• Four steps in the process of statistics . CORRECT ANSWER: 1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
• Categorical variable . CORRECT ANSWER: places individuals into one of
several groups
Two types: nominal and ordinal
• Quantitative Variable . CORRECT ANSWER: represents a measurement or a
count
Two types: Interval and ratio
• Nominal Variable . CORRECT ANSWER: categorical variables where there is
no natural order among the categories
• Ordinal variable . CORRECT ANSWER: categorical variables where there is
natural order among the categories
• Interval Variable . CORRECT 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 . CORRECT 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 . CORRECT ANSWER: nominal
• What type of variable?:
socioeconomic status with categories low, med, high . CORRECT ANSWER:
Ordinal
, • What type of variable?:
Temperature . CORRECT ANSWER: Interval
• What type of variable?:
Income . CORRECT ANSWER: Ratio
• Visual display and numerical summary for a single categorical variable .
CORRECT ANSWER: pie chart or bar chart
and category percentages
• Visual display and numerical summary for a single quantitative variable .
CORRECT ANSWER: histogram or stemplot
and descriptive statistics
• Visual display and numerical summary for C->C . CORRECT ANSWER: Two
way table and conditional percentages
• Visual display and numerical summary for C->Q . CORRECT ANSWER: Side
by side box plots and descriptive statistics
• Visual display and numerical summary for Q->Q . CORRECT ANSWER:
Scatterplot and correlation coefficient (r)
• Standard Deviation Rule . CORRECT ANSWER: 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 ANSWER: Middle 50% of the data
IQR= Q3-Q1
• Finding an outlier using IQR . CORRECT ANSWER: 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 ANSWER: 1. upward slope
2. downward slope
RECENT EXAM UPDATED ACTUAL Exam Question
and Answer (2026/2027) | Detailed Rationales
• Four steps in the process of statistics . CORRECT ANSWER: 1. Producing Data
2. Exploratory Data Analysis
3. Probability
4. Inference
• Categorical variable . CORRECT ANSWER: places individuals into one of
several groups
Two types: nominal and ordinal
• Quantitative Variable . CORRECT ANSWER: represents a measurement or a
count
Two types: Interval and ratio
• Nominal Variable . CORRECT ANSWER: categorical variables where there is
no natural order among the categories
• Ordinal variable . CORRECT ANSWER: categorical variables where there is
natural order among the categories
• Interval Variable . CORRECT 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 . CORRECT 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 . CORRECT ANSWER: nominal
• What type of variable?:
socioeconomic status with categories low, med, high . CORRECT ANSWER:
Ordinal
, • What type of variable?:
Temperature . CORRECT ANSWER: Interval
• What type of variable?:
Income . CORRECT ANSWER: Ratio
• Visual display and numerical summary for a single categorical variable .
CORRECT ANSWER: pie chart or bar chart
and category percentages
• Visual display and numerical summary for a single quantitative variable .
CORRECT ANSWER: histogram or stemplot
and descriptive statistics
• Visual display and numerical summary for C->C . CORRECT ANSWER: Two
way table and conditional percentages
• Visual display and numerical summary for C->Q . CORRECT ANSWER: Side
by side box plots and descriptive statistics
• Visual display and numerical summary for Q->Q . CORRECT ANSWER:
Scatterplot and correlation coefficient (r)
• Standard Deviation Rule . CORRECT ANSWER: 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 ANSWER: Middle 50% of the data
IQR= Q3-Q1
• Finding an outlier using IQR . CORRECT ANSWER: 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 ANSWER: 1. upward slope
2. downward slope
