C784 STATISTICS FULL COURSE
REVIEW QUESTIONS WITH ACTUAL
ANSWERS 2025/2026
Lurking Variable - ANSWERSAssociated with the explanatory and the response
variables that is not directly being studied.
Simpson's Paradox - ANSWERSOccurs when a trend or result that appears in groups of
data disappears when we combine the data.
Regression Analysis - ANSWERSA process for estimating and analyzing the
relationship between variables.
Least-Squares Regression Line - ANSWERSAKA the line of best fit.
y = mx + b
"rise over run"
Interpolation - ANSWERSUsing existing data along with the Least-Squares Regression
Line to make a prediction.
Extrapolation - ANSWERSEstimation by projecting OUTSIDE known data points.
p-value - ANSWERSthe probability that a result occurred by chance
Significance Levels in Hypothesis Testing - ANSWERSStatistically Significant: If a
measured p-value is less than the significance level.
NOT Statistically Significant: If a measured p-value is MORE than the significance level.
Empirical Rule - ANSWERS68 - 95 - 99.7
68% is w/in 1 standard deviation of the mean
95% is w/in 1 standard deviation of the mean
99.7% is w/in 1 standard deviation of the mean
Used for Categorical (Qual) Data - ANSWERSBar Chart
Pie Chart
Mean - ANSWERSAverage - adding series then dividing by the total number in that
series
, Center & Spread Measures - ANSWERSSYMMETRIC - Mean (center) / Standard
Deviation (spread)
SKEWED - Median (center) / IQR (spread)
CATEGORICAL - Mode (center) / no spread
What is the difference between a bar chart and a histogram? - ANSWERSBAR CHART
- Categorical data distributed over groups of categories
HISTOGRAM - Quantitative data distributed over various intervals
Outlier Formula - ANSWERS1.5 x IQR above Q3 or below Q1
Graphical Displays for Quantitative Variables - ANSWERSHISTOGRAMS - large data
sets
STEM PLOTS - keeps individual data points
DOT PLOTS - smaller data sets
BOX PLOTS - center, spread and 5 number summary
SCATTER PLOTS - x,y axis
5 Number Summary - ANSWERSMin - Q1 - Median - Q3 - Max
Define Explanatory vs Response Variable - ANSWERSEXPLANATORY VARIABLE
(x/independent) - presumed to possible cause change in the response variable
RESPONSE VARIABLE (y/dependent) presumed to be affected by the explanatory
variable
Correlation Coefficient - ANSWERSaka "r", describes the direction and strength of the
relationship of variables on a scatterplot.
Between -1 and +1
0 = no correlation
-1 = perfect negative correlation
1 = perfect positive correlation
Empirical (Observational) Probability - ANSWERSThis is based on an experiment.
Relative frequency of an event = number of times event occurs / total number of trials
Graphical Displays and Corresponding Numerical Analysis Tools for Examining Data
Relationships - ANSWERSC > C - Two-way Frequency Tables (aka Contingency Table)
use conditional percentages and relative frequencies
REVIEW QUESTIONS WITH ACTUAL
ANSWERS 2025/2026
Lurking Variable - ANSWERSAssociated with the explanatory and the response
variables that is not directly being studied.
Simpson's Paradox - ANSWERSOccurs when a trend or result that appears in groups of
data disappears when we combine the data.
Regression Analysis - ANSWERSA process for estimating and analyzing the
relationship between variables.
Least-Squares Regression Line - ANSWERSAKA the line of best fit.
y = mx + b
"rise over run"
Interpolation - ANSWERSUsing existing data along with the Least-Squares Regression
Line to make a prediction.
Extrapolation - ANSWERSEstimation by projecting OUTSIDE known data points.
p-value - ANSWERSthe probability that a result occurred by chance
Significance Levels in Hypothesis Testing - ANSWERSStatistically Significant: If a
measured p-value is less than the significance level.
NOT Statistically Significant: If a measured p-value is MORE than the significance level.
Empirical Rule - ANSWERS68 - 95 - 99.7
68% is w/in 1 standard deviation of the mean
95% is w/in 1 standard deviation of the mean
99.7% is w/in 1 standard deviation of the mean
Used for Categorical (Qual) Data - ANSWERSBar Chart
Pie Chart
Mean - ANSWERSAverage - adding series then dividing by the total number in that
series
, Center & Spread Measures - ANSWERSSYMMETRIC - Mean (center) / Standard
Deviation (spread)
SKEWED - Median (center) / IQR (spread)
CATEGORICAL - Mode (center) / no spread
What is the difference between a bar chart and a histogram? - ANSWERSBAR CHART
- Categorical data distributed over groups of categories
HISTOGRAM - Quantitative data distributed over various intervals
Outlier Formula - ANSWERS1.5 x IQR above Q3 or below Q1
Graphical Displays for Quantitative Variables - ANSWERSHISTOGRAMS - large data
sets
STEM PLOTS - keeps individual data points
DOT PLOTS - smaller data sets
BOX PLOTS - center, spread and 5 number summary
SCATTER PLOTS - x,y axis
5 Number Summary - ANSWERSMin - Q1 - Median - Q3 - Max
Define Explanatory vs Response Variable - ANSWERSEXPLANATORY VARIABLE
(x/independent) - presumed to possible cause change in the response variable
RESPONSE VARIABLE (y/dependent) presumed to be affected by the explanatory
variable
Correlation Coefficient - ANSWERSaka "r", describes the direction and strength of the
relationship of variables on a scatterplot.
Between -1 and +1
0 = no correlation
-1 = perfect negative correlation
1 = perfect positive correlation
Empirical (Observational) Probability - ANSWERSThis is based on an experiment.
Relative frequency of an event = number of times event occurs / total number of trials
Graphical Displays and Corresponding Numerical Analysis Tools for Examining Data
Relationships - ANSWERSC > C - Two-way Frequency Tables (aka Contingency Table)
use conditional percentages and relative frequencies
