Data Manipulation

What is the primary purpose of the 'dplyr' package in R?

Statistical modeling

Data visualization

Data manipulation

Machine learning

Which function is used to filter rows based on specified conditions in dplyr?

Subset()

Filter()

Select()

Arrange()

What does the group_by() function do in 'dplyr'?

Creates a new column

Filters rows based on conditions

Groups data by one or more columns

Sorts data frame by column values

Which operator is used for chaining operations in dplyr?

%<>%

%$%

%>%

%|%

How do you calculate the mean of a numeric column in a grouped data frame using dplyr?

Group_mean()

Mean_grouped()

Aggregate(mean)

Summarize(mean=mean(column))

What does the mutate() function do in dplyr?

Filters rows based conditions

Groups data by one or more columns

Creates or modifies columns

Sorts data frame by column values

Which function is used to arrange rows based on column values in ascending order in dplyr?in

Order()

Arrange()

Sort()

Ascending()

What does the select function do in dplyr?

Choose specific columns

Renames columns

Filters rows based on conditions

Groups data by one or more columns

How can you remove duplicate rows based on selected columns in dplyr?

Remove_duplicates()

Distinct()

Unique_rows()

Dedup()

Which function is used to calculate the total number of rows in a data frame?

Count()

Total_rows()

N()

Length()

How do you create a new variable in a data frame based on existing variables using dplyr?

Modify()

Create_var()

Transform()

Mutate()

In dplyr what does the %in% operator check for?

Equality

Inequality

Presence in a vector

Absence in a vector

What does na.omit() function do in R?

Replaces missing values with the mean of the column

Removes rows with missing values

Imputes missing values with zeros

Fills missing values with the previous non-missing value

What does the is.na() function in R do?

Identifies missing values in a vector or data frame

Checks if a vector is numeric

Computes the mean of a numeric vector

Filters rows based on conditions

What is the purpose of the complete.cases() function in R?

Completes missing values with the mean of the column

Identifies cases with complete data(no missing values)

Adds new cases to a data frame

Computes summary statistics for complete cases

How do you filter rows with missing values in a specific column, say "Age", using dplyr?

Filter(data, is.na(Age))

Filter(data, Age==NA)

Filter(data, Age %in% NA)

Filter(data, !complete.cases(Age))

Data Manipulation

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