Data Analysis Techniques Quiz

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Questions and Answers

In Unsupervised Learning, what determines the outcome of the algorithm?

The programmer inputs the correct answers for the algorithm to learn from.

The algorithm itself identifies patterns and relationships within the data. (correct)

The algorithm is guided by a control algorithm, which makes decisions during the process.

There are labels attached to the data, allowing the algorithm to predict future outcomes based on labeled examples.

Which of the following correctly describes the difference between Classification and Regression?

Classification analyzes categorical data, while regression focuses on numerical data.

Classification uses numerical labels, while regression uses categorical labels.

Classification involves categorizing data points into discrete groups, while regression predicts continuous values. (correct)

Classification predicts the likelihood of future events, while regression attempts to explain the relationship between variables.

What is the main purpose of a Violin Plot?

To visualize the distribution of data points by overlaying a box plot with a kernel density estimation. (correct)

To map sound waves from the time domain to the frequency domain.

To measure the accuracy of a classification model based on decibel units.

To display the frequency of occurrence of a specific value within a dataset.

What does the regular expression `r'\b[Aa]\w+'` match?

Words that start with either an uppercase or lowercase 'A'. (A) Signup and view all the answers

Which of the following is NOT a bias that could affect data analysis?

Correlation bias: assuming a causal relationship between correlated variables. (C) Signup and view all the answers

Which Python library is primarily used for data analysis and manipulation?

Pandas (B) Signup and view all the answers

Which of the following best describes the purpose of Visualization in data analysis?

Communicating information effectively to a target audience. (D) Signup and view all the answers

What does the code `df[df['column1'] > df['column1'].mean() + 3 * df['column1'].std]` achieve?

It identifies rows where the value in 'column1' is greater than 3 standard deviations above the mean. (D) Signup and view all the answers

What is the purpose of the code segment `q1 = df['column1'].quantile(0.25)`?

Find the 25th percentile of the 'column1' column. (C) Signup and view all the answers

What does the code `iqr = q3 - q1` calculate?

The distance between the 25th and 75th percentiles of 'column1'. (C) Signup and view all the answers

What is the purpose of the code `df[(df['column1'] < q1 - 1.5 * iqr) | (df['column1'] > q3 + 1.5 * iqr)]`?

It identifies rows where 'column1' values are more than 1.5 IQRs away from both the 25th and 75th percentiles. (B) Signup and view all the answers

Which of these techniques can be used to handle outliers, based on the provided code snippets?

Removing the outliers from the dataset. (A), Replacing outliers with the mean value of 'column1'. (B), Transforming the 'column1' values using a log transformation. (C) Signup and view all the answers

Which of the following commands is used to obtain the content of the response in a given network request?

response.text() (D) Signup and view all the answers

Which library is commonly imported for creating visualizations in Python? (Select all that apply)

matplotlib.pyplot (B), plotly (C) Signup and view all the answers

Which code snippet correctly adds a legend to a graph in matplotlib.pyplot, assuming plt is imported?

plt.legend() (B) Signup and view all the answers

In the provided code snippet, how can you replace missing values in a pandas DataFrame with the mean of each column? (Select all that apply)

df = df.replace(np.nan, df.mean()) (C), None of the above (E) Signup and view all the answers

Which of the following options is an example of an unsupervised learning model?

Kmeans (C) Signup and view all the answers

What is the primary use case of the Scikit-learn library in Python?

Machine learning tasks (D) Signup and view all the answers

Which of the following machine learning algorithms is categorized as a supervised learning algorithm?

SVM (Support Vector Machine) (B) Signup and view all the answers

How can you use the K-Means algorithm from the Scikit-learn library?

from sklearn.cluster import KMeans (A) Signup and view all the answers

Which of the following describes a common use case for the `fillna()` function in pandas?

Replacing missing values with a specific value (C) Signup and view all the answers

What is the purpose of the code snippet: `df = pd.DataFrame({'A': [1, 2, np.nan, 4, 5], 'B': [3, np.nan, np.nan, 8, 9], 'C': [10, 11, 12, np.nan, 14]})`?

To create a Pandas DataFrame with specific values (C) Signup and view all the answers

What is the main difference between supervised and unsupervised learning?

Supervised learning uses labeled data, while unsupervised learning uses unlabeled data. (A) Signup and view all the answers

What does the command `df.loc[df['A'].isnull(), 'B'] = df['B'].mean()` accomplish in a Pandas DataFrame?

It fills missing values (NaN) in column 'B' with the mean of column 'B', only for the rows where the value in 'A' is NaN. (D) Signup and view all the answers

Which of these is the correct Python code for calculating the IQR (Interquartile Range) of a column named 'column1' in a Pandas DataFrame named 'df'?

<code>df['column1'].quantile(0.75) - df['column1'].quantile(0.25)</code> (C) Signup and view all the answers

Suppose you have determined the IQR of 'column1' in a DataFrame. How would you identify outliers using this IQR?

Any value in 'column1' that is greater than Q3 + 1.5 * IQR or less than Q1 - 1.5 * IQR is an outlier. (A) Signup and view all the answers

What is the purpose of using the IQR method to identify outliers?

To find values that are significantly different from the rest of the data. (D) Signup and view all the answers

What is the primary advantage of using the `loc` attribute in Pandas DataFrames?

It allows you to access and modify data based on integer row and column labels. (B) Signup and view all the answers

Which of these is a function of the `isnull()` method used in the code snippet?

It identifies missing values in a Pandas DataFrame. (D) Signup and view all the answers

In the code snippet, what does the symbol `'B'` within the `df.loc[df['A'].isnull(), 'B']` assignment represent?

The name of the column to be modified. (D) Signup and view all the answers

The command `df['B'].mean()` in the code snippet directly calculates which statistical measure?

The average value of column 'B'. (B) Signup and view all the answers

What is the main potential risk associated with replacing missing data (like NaN) with the mean value (as done in the code)?

It might create an outlier affecting the distribution of the data. (C) Signup and view all the answers

Which of the following is NOT a typical approach to handle outliers in a dataset?

Identifying the outliers and marking them without modification. (D) Signup and view all the answers

Flashcards

Supervised Learning

Learning with labeled data where the model is trained on input-output pairs.

Unsupervised Learning

Learning without labeled responses, allowing the model to identify patterns independently.