Misy262 FINAL EXAM QUESTIONS
AND ANSWERS
what do you use $ for ? - ANSWER-use $ to find statistics for a specific column
unlike other types of data analysis, descriptive statistics does NOT attempt to ...... -
ANSWER-unlike other types of data analysis, descriptive statistics does NOT
attempt to make predictions about the future
what does the attch() method do? - ANSWER-attach() is used to specify the dataset
using and let R know we are reffering to it so so we dont need to keep repeating the
dataset name
an outlier is an ____ value in a dataset - ANSWER-unusual
categorical values need to be stored as ..... - ANSWER-factors
missing values in datasets have no effect on calculations such as mean or std
calculations - ANSWER-false
the use of mean value ito impute the data is simple and considered the best practice
to deal with missing data - ANSWER-false
what data imputation method is best for dealing with missing values in the
categorical variables ? - ANSWER-imputation by random forest
____ means that missing data systematically differs from the observed values -
ANSWER-MNAR
what package do we use to deal with missing values ? - ANSWER-mice package
which packages can we use to get statistics for a dataset ? - ANSWER-pastecs and
psych
which method do we use to get the summary statistics for all variables by group
based on categorical variables ? - ANSWER-describeBy()
What method is used to create a linear regression model ? - ANSWER-lm( )
the box plot in the x axis , must it be categorical or factor variable ? - ANSWER-
categorical
by default will the box plot give you the mean ? - ANSWER-no
what method do we use to write titles? - ANSWER-labs()
what is the second step of EDA? - ANSWER-data visualization
, how do you plot a histogram ? - ANSWER-geom_histogram
if it is pre counted you use what ?
if it is NOT pre counted you use what ? - ANSWER-pre counted = column chart
NOT pre counted = bar chart
geom_bar only needs 1 variable in the X axis, y will already be provided - ANSWER-
true
if you do geom_bar with 2 variables, what will happen - ANSWER-it will give an error
to change the width so its equal, what code do you use ? - ANSWER-
geom_bar(position=position_dodge(preserve="single")
to change the legend position to the top do theme(legend.position='top') - ANSWER-
true
to have no legend at all do theme(legend.positon='none') - ANSWER-true
geom_col and geom_bar have no differences - ANSWER-false
you can change the background color for the bar of the plot - ANSWER-false
how to save - ANSWER-ggsave
what does which(is.na()) do? - ANSWER-returns indices(the place) of the missing
values
what does na.rm=TRUE do ? - ANSWER-it removes the missing values from a
specific calculation
what does n_miss() do ? - ANSWER-returns the number of missing values
what does pct_miss() do ? - ANSWER-returns the percentage of missing values
what does pct_miss_case() do ? - ANSWER-returns the percentage of rows WITH
missing values
what does vis _miss() do ? - ANSWER-returns a heat map of missing values
what does gg_ miss_ var(dataset_ name, show _pct=TRUE) do ? - ANSWER-
returns the percentage of missing values in each variable in a dataset in a form of a
graph
the box plot in the x axis , must it be categorical or factor variable ? - ANSWER-
categorical
by default will the box plot give you the mean ? - ANSWER-no
AND ANSWERS
what do you use $ for ? - ANSWER-use $ to find statistics for a specific column
unlike other types of data analysis, descriptive statistics does NOT attempt to ...... -
ANSWER-unlike other types of data analysis, descriptive statistics does NOT
attempt to make predictions about the future
what does the attch() method do? - ANSWER-attach() is used to specify the dataset
using and let R know we are reffering to it so so we dont need to keep repeating the
dataset name
an outlier is an ____ value in a dataset - ANSWER-unusual
categorical values need to be stored as ..... - ANSWER-factors
missing values in datasets have no effect on calculations such as mean or std
calculations - ANSWER-false
the use of mean value ito impute the data is simple and considered the best practice
to deal with missing data - ANSWER-false
what data imputation method is best for dealing with missing values in the
categorical variables ? - ANSWER-imputation by random forest
____ means that missing data systematically differs from the observed values -
ANSWER-MNAR
what package do we use to deal with missing values ? - ANSWER-mice package
which packages can we use to get statistics for a dataset ? - ANSWER-pastecs and
psych
which method do we use to get the summary statistics for all variables by group
based on categorical variables ? - ANSWER-describeBy()
What method is used to create a linear regression model ? - ANSWER-lm( )
the box plot in the x axis , must it be categorical or factor variable ? - ANSWER-
categorical
by default will the box plot give you the mean ? - ANSWER-no
what method do we use to write titles? - ANSWER-labs()
what is the second step of EDA? - ANSWER-data visualization
, how do you plot a histogram ? - ANSWER-geom_histogram
if it is pre counted you use what ?
if it is NOT pre counted you use what ? - ANSWER-pre counted = column chart
NOT pre counted = bar chart
geom_bar only needs 1 variable in the X axis, y will already be provided - ANSWER-
true
if you do geom_bar with 2 variables, what will happen - ANSWER-it will give an error
to change the width so its equal, what code do you use ? - ANSWER-
geom_bar(position=position_dodge(preserve="single")
to change the legend position to the top do theme(legend.position='top') - ANSWER-
true
to have no legend at all do theme(legend.positon='none') - ANSWER-true
geom_col and geom_bar have no differences - ANSWER-false
you can change the background color for the bar of the plot - ANSWER-false
how to save - ANSWER-ggsave
what does which(is.na()) do? - ANSWER-returns indices(the place) of the missing
values
what does na.rm=TRUE do ? - ANSWER-it removes the missing values from a
specific calculation
what does n_miss() do ? - ANSWER-returns the number of missing values
what does pct_miss() do ? - ANSWER-returns the percentage of missing values
what does pct_miss_case() do ? - ANSWER-returns the percentage of rows WITH
missing values
what does vis _miss() do ? - ANSWER-returns a heat map of missing values
what does gg_ miss_ var(dataset_ name, show _pct=TRUE) do ? - ANSWER-
returns the percentage of missing values in each variable in a dataset in a form of a
graph
the box plot in the x axis , must it be categorical or factor variable ? - ANSWER-
categorical
by default will the box plot give you the mean ? - ANSWER-no
