Python Pandas/MatPlotLib

What does df.groupby('column_name').mean() do in Pandas?

• Groups the DataFrame by 'column_name' and calculates the mean of all columns

• Finds the mean value of 'column_name'

• Splits the DataFrame into groups based on 'column_name' and calculates the mean of each group

• Sorts 'column_name' in ascending order

In Pandas, how do you select the rows where the column 'age' is greater than 25?

• df[df['age'] > 25]

• df.select('age' > 25)

• df.query('age' > 25)

• df['age'].select(> 25)

How would you save a plot as a PNG file in Matplotlib?

• plt.savefig('plot.png')

• plt.save('plot.png')

• plt.export('plot.png')

• plt.write('plot.png')

In Pandas, what does df.isnull().sum() return?

• The sum of all values in the DataFrame

• The total number of missing values in each column

• A boolean value indicating if there are any null values

• The sum of non-null values in the DataFrame

Which method is used to read a CSV file into a Pandas DataFrame?

• pd.read_csv('file.csv')

• pd.csv('file.csv')

• pd.readfile('file.csv')

• pd.open_csv('file.csv')

In Matplotlib, how do you set the title of a plot?

• plt.title('My Title')

• plt.set_title('My Title')

• plt.name('My Title')

• plt.label('My Title')

How can you create a new column in a DataFrame in Pandas?

• df['new_column'] = value

• df.add('new_column', value)

• df.new_column(value)

• df.insert('new_column', value)

What does df.merge(other_df, on='key') do in Pandas?

• Concatenates df and other_df based on 'key'

• Performs an inner join between df and other_df on the 'key' column

• Merges the two DataFrames on the index

• Replaces the 'key' column in df with that in other_df

In Matplotlib, which function is used to display a histogram?

• plt.bar()

• plt.plot()

• plt.hist()

• plt.scatter()

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