WGU C955 EXAM APPLIED PROBABILITY
AND STATISTICS EXAM STUDY GUIDE |
RATED A+ | 2024/2025 GUIDE
Mode
- Correct Answer - The value that occurs most frequently in a
given data set.
Median
- Correct Answer - the middle score in a distribution; half the
scores are above it and half are below it
Mean
- Correct Answer - Average, extreme values greatly influence
the mean in the direction of the skew
Range
- Correct Answer - the difference between the highest and
lowest scores in a distribution
InterQuartile Range (IQR)
,- Correct Answer - the difference between the first and third
quartiles
Quartiles
- Correct Answer - Values that divide a data set into four equal
parts
Second Quartile
- Correct Answer - The median of the data set
First Quartile
- Correct Answer - The median of the lower half of the data set
Third Quartile
- Correct Answer - The median of the upper half of the data set
Standard Deviation
- Correct Answer - The average distance each data point is
from the mean
Empirical Rule
- Correct Answer - For the normal distribution (bell-shaped
distribution), approximately 68% of the measurements are within
,one standard deviation of the mean, approximately 95% of the
measurements are within two standard deviations of the mean,
and approximately 99.7% of the measurements are within three
standard deviations of the mean.
Which measures of center and spread should you use?
- Correct Answer - Normal, symmetric data: Use the mean and
standard deviation.
Skewed: Use the median or IQR.
Categorical: Use the mode and no measure of spread.
Misrepresenting Data with Visualizations
- Correct Answer - Scale of Axis: The vertical scale should start
at 0.
Omitting Labels or Units: Leaves the size and categories
unspecified.
Using a 2-dimensional graph to represent a 1 dimensional
measurement: When visualizing data that represents size (big
circle vs small circle), our eyes see area. This distorts the true
differences we are trying to illustrate.
Explanatory Variable (Relationship between two variables)
, - Correct Answer - (x) - presumed to possibly cause changes in
the response variable; also known as the independent variable.
A variable that helps explain or influences changes in a response
variable. Otherwise known as an independent variable.
Response Variable (Relationship between two variables)
- Correct Answer - (y) - presumed to be affected by the
explanatory variable; also known as the dependent variable.
Variable affected by an explanatory variable. Otherwise knows as
a dependent variable.
Graphical Displays of Two Variable Data
- Correct Answer - Categorical: Categorical, (C -> C), Two-way
table
Categorical: Quantitative, (C -> Q), Side-by-side Box Plot
Quantitative: Quantitative, (Q -> Q), Scatterplot
Two-way Frequency Table (Contingency Table)
- Correct Answer - C -> Q, rows show one variables categories,
columns, columns show the other variable's categories
Joint Frequencies
AND STATISTICS EXAM STUDY GUIDE |
RATED A+ | 2024/2025 GUIDE
Mode
- Correct Answer - The value that occurs most frequently in a
given data set.
Median
- Correct Answer - the middle score in a distribution; half the
scores are above it and half are below it
Mean
- Correct Answer - Average, extreme values greatly influence
the mean in the direction of the skew
Range
- Correct Answer - the difference between the highest and
lowest scores in a distribution
InterQuartile Range (IQR)
,- Correct Answer - the difference between the first and third
quartiles
Quartiles
- Correct Answer - Values that divide a data set into four equal
parts
Second Quartile
- Correct Answer - The median of the data set
First Quartile
- Correct Answer - The median of the lower half of the data set
Third Quartile
- Correct Answer - The median of the upper half of the data set
Standard Deviation
- Correct Answer - The average distance each data point is
from the mean
Empirical Rule
- Correct Answer - For the normal distribution (bell-shaped
distribution), approximately 68% of the measurements are within
,one standard deviation of the mean, approximately 95% of the
measurements are within two standard deviations of the mean,
and approximately 99.7% of the measurements are within three
standard deviations of the mean.
Which measures of center and spread should you use?
- Correct Answer - Normal, symmetric data: Use the mean and
standard deviation.
Skewed: Use the median or IQR.
Categorical: Use the mode and no measure of spread.
Misrepresenting Data with Visualizations
- Correct Answer - Scale of Axis: The vertical scale should start
at 0.
Omitting Labels or Units: Leaves the size and categories
unspecified.
Using a 2-dimensional graph to represent a 1 dimensional
measurement: When visualizing data that represents size (big
circle vs small circle), our eyes see area. This distorts the true
differences we are trying to illustrate.
Explanatory Variable (Relationship between two variables)
, - Correct Answer - (x) - presumed to possibly cause changes in
the response variable; also known as the independent variable.
A variable that helps explain or influences changes in a response
variable. Otherwise known as an independent variable.
Response Variable (Relationship between two variables)
- Correct Answer - (y) - presumed to be affected by the
explanatory variable; also known as the dependent variable.
Variable affected by an explanatory variable. Otherwise knows as
a dependent variable.
Graphical Displays of Two Variable Data
- Correct Answer - Categorical: Categorical, (C -> C), Two-way
table
Categorical: Quantitative, (C -> Q), Side-by-side Box Plot
Quantitative: Quantitative, (Q -> Q), Scatterplot
Two-way Frequency Table (Contingency Table)
- Correct Answer - C -> Q, rows show one variables categories,
columns, columns show the other variable's categories
Joint Frequencies
