Straighterline Introduction to Statistics Exam
Questions and Answers
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
, Straighterline Introduction to Statistics Exam
Questions and Answers
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
Visual display and numerical summary for C->C - ANSWER: Two way
table and conditional percentages
Visual display and numerical summary for C->Q - ANSWER: Side by side
box plots and descriptive statistics
Visual display and numerical summary for Q->Q - ANSWER: Scatterplot
and correlation coefficient (r)
Standard Deviation Rule - ANSWER: Approximately
68% of observations fall within 1 sd of the mean,
95% within 2 sd,
99.7% (or virtually all) within 3 sds
!@#$%^)
Interquartile Range (IQR) - ANSWER: Middle 50% of the data
(*&^%$!
IQR= Q3-Q1
@#$%^&
*&^%$#
Finding an outlier using IQR - 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 -ANSWER: 1. upward slope
2. downward slope
Questions and Answers
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
, Straighterline Introduction to Statistics Exam
Questions and Answers
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
Visual display and numerical summary for C->C - ANSWER: Two way
table and conditional percentages
Visual display and numerical summary for C->Q - ANSWER: Side by side
box plots and descriptive statistics
Visual display and numerical summary for Q->Q - ANSWER: Scatterplot
and correlation coefficient (r)
Standard Deviation Rule - ANSWER: Approximately
68% of observations fall within 1 sd of the mean,
95% within 2 sd,
99.7% (or virtually all) within 3 sds
!@#$%^)
Interquartile Range (IQR) - ANSWER: Middle 50% of the data
(*&^%$!
IQR= Q3-Q1
@#$%^&
*&^%$#
Finding an outlier using IQR - 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 -ANSWER: 1. upward slope
2. downward slope
