In time-series data, creating lag features involves using previous time steps as new _______.

  • Predictors
  • Observations
  • Predictions
  • Variables
In time-series analysis, creating lag features means using previous time steps (observations) as new data points. This allows you to incorporate historical information into your model, which can be valuable for forecasting future values in time series data.

In the context of outlier detection, what is the commonly used plot to visually detect outliers in a single variable?

  • Box Plot
  • Scatter Plot
  • Histogram
  • Line Chart
A Box Plot is a commonly used visualization for detecting outliers in a single variable. It displays the distribution of data and identifies potential outliers based on the interquartile range (IQR). Data points outside the whiskers of the box plot are often considered outliers. Box plots are useful for identifying data anomalies.

Which step in the Data Science Life Cycle is concerned with cleaning the data and handling missing values?

  • Data Exploration
  • Data Collection
  • Data Preprocessing
  • Data Visualization
Data Preprocessing is the step in the Data Science Life Cycle that involves cleaning the data, handling missing values, and preparing it for analysis. This step is crucial for ensuring the quality and reliability of the data used in subsequent analysis.

What is the most common measure of central tendency, which calculates the average value of a dataset?

  • Median
  • Mode
  • Mean
  • Standard Deviation
The mean, also known as the average, is a common measure of central tendency. It's calculated by adding up all the values in the dataset and then dividing by the number of data points. The mean provides a sense of the "typical" value in the dataset.

In the context of binary classification, which metric calculates the ratio of true positives to the sum of true positives and false negatives?

  • Precision-Recall Curve
  • F1 Score
  • True Positive Rate (Sensitivity)
  • Specificity
The True Positive Rate, also known as Sensitivity or Recall, calculates the ratio of true positives to the sum of true positives and false negatives. It measures the model's ability to correctly identify positive cases. It is an important metric in binary classification evaluation.

Which method for handling missing data involves using algorithms like k-NN to find similar records to impute the missing value?

  • Mean imputation
  • Median imputation
  • k-NN imputation
  • Mode imputation
k-NN imputation is a technique that uses the similarity of data points to impute missing values. It finds records with similar characteristics to the one with missing data and replaces the missing value with the imputed value from its nearest neighbors. Other options are simpler imputation methods.

In recurrent neural networks (RNNs), which variant is designed specifically to handle long-term dependencies by maintaining a cell state?

  • LSTM (Long Short-Term Memory)
  • GRU (Gated Recurrent Unit)
  • SRU (Simple Recurrent Unit)
  • ESN (Echo State Network)
Long Short-Term Memory (LSTM) is a variant of RNN designed to handle long-term dependencies by maintaining a cell state that can capture information over long sequences. LSTM's ability to store and retrieve information over extended time steps makes it well-suited for tasks involving long-term dependencies in data sequences.

Which metric provides a single score that balances the trade-off between precision and recall?

  • F1 Score
  • Accuracy
  • ROC AUC
  • Log Loss
The F1 Score is a metric that balances the trade-off between precision and recall. It is especially useful when dealing with imbalanced datasets or when you want to find a balance between correctly identifying positive cases (precision) and capturing all positive cases (recall). The F1 Score is the harmonic mean of precision and recall. It is a suitable choice for evaluating models when both precision and recall are essential.

Data formats that allow for tagging or marking up of data, giving it some level of organization, often fall into the _______ data category.

  • Raw data
  • Structured data
  • NoSQL data
  • XML data
Data formats like XML allow for tagging or marking up data, which gives it a structured organization. XML is an example of semi-structured data, where data elements are labeled, providing some level of organization.

Random Forest is an ensemble technique that builds multiple:

  • Decision trees
  • Linear regression models
  • Neural networks
  • Support vector machines
Random Forest is an ensemble method that builds multiple decision trees. These decision trees are used to make predictions and are combined to create a more accurate and robust model. Random Forest is known for its ability to reduce overfitting and provide reliable predictions, making it a popular choice in machine learning.