Mixed Deck — All DSE Topics Flashcards

Which type of map visualization is best suited for showing a continuous variable (e.g., population density) distributed across geographic regions?

Answer: Choropleth map

A choropleth map shades geographic regions by intensity of a variable, making spatial patterns in continuous data (like income or population density) immediately visible.

When using RMSE versus MAE to evaluate regression models, RMSE is preferred when:

Answer: Large errors are particularly undesirable

RMSE squares errors before averaging, so it penalizes large errors more heavily than MAE, making it preferable when large deviations are costly.

What does the Autocorrelation Function (ACF) measure in time series analysis?

Answer: The correlation between a time series and a lagged version of itself

The ACF measures the correlation between a time series and its own lagged values at different time lags, helping identify patterns and the order of MA terms.

Which technique specifically addresses class imbalance by generating synthetic samples for the minority class?

Answer: SMOTE

SMOTE (Synthetic Minority Over-sampling Technique) creates new synthetic samples by interpolating between existing minority class examples.

What is Apache Sqoop primarily used for?

Answer: Bulk transfer of data between relational databases and Hadoop

Sqoop is designed to efficiently transfer bulk data between relational databases (via JDBC) and Hadoop storage systems like HDFS or HBase.

A researcher sets α = 0.01 instead of α = 0.05. What is the direct consequence?

Answer: Reduced probability of a Type I error

Lowering α makes the rejection region smaller, directly reducing the probability of falsely rejecting a true null hypothesis (Type I error).

The false discovery rate (FDR), controlled by the Benjamini-Hochberg procedure, is defined as:

Answer: The expected proportion of rejected nulls that are false rejections

FDR = E[V/R] where V is false rejections and R is total rejections; BH controls this expected proportion, offering more power than Bonferroni.

What is statistical modeling's shared objective?

Answer: Inference

Statistical modeling's primary objective is to draw conclusions or make predictions about a larger population based on a sample of data. This process of generalizing from a sample to a population is known as statistical inference. While models can summarize data, their core purpose is to make informed inferences about underlying relationships or future outcomes.

What is the main advantage of using quantile transformation over standard normalization for highly skewed data?

Answer: It maps values to a uniform or normal distribution, making it robust to outliers

Quantile transformation maps data to a target distribution based on rank, making it robust to extreme outliers unlike mean/std-based scaling.

Which technique adjusts a classifier's predicted probabilities to be better calibrated without retraining it?

Answer: Platt scaling

Platt scaling fits a logistic regression on the model's raw outputs to transform them into calibrated probabilities.

Which of the following is an example of 'automation bias' in an AI-assisted medical diagnostic system?

Answer: Clinicians over-rely on the AI recommendation and skip their own assessment

Automation bias is the tendency for humans to defer to automated systems even when their own judgment would yield a better result.

In transformer architectures, what is the purpose of positional encoding?

Answer: To inject sequence order information since attention is permutation-invariant

Self-attention has no inherent notion of order, so positional encodings are added to embeddings to convey token position.

The ROC curve plots which two quantities against each other?

Answer: True Positive Rate vs. False Positive Rate

The ROC curve plots the True Positive Rate (sensitivity) on the y-axis against the False Positive Rate (1 - specificity) on the x-axis.

In EDA, what is a 'rug plot'?

Answer: Tick marks along an axis showing individual data point locations

A rug plot places short vertical tick marks along an axis at each data point's position, showing the actual distribution of individual observations.

Which of the following activation functions is used in the output layer of a neural network for binary classification?

Answer: Sigmoid

The sigmoid function maps the output to a value between 0 and 1, which can be interpreted as the probability of the positive class.

The concept of 'value alignment' in AI safety refers to:

Answer: Ensuring AI systems pursue goals consistent with human values and intentions

Value alignment ensures that as AI systems become more capable, their objectives remain consistent with what humans actually want and care about.

When applying K-Means to text data represented as TF-IDF vectors, which distance metric is typically preferred?

Answer: Cosine similarity

Cosine similarity measures the angle between document vectors regardless of magnitude, making it more appropriate for high-dimensional sparse TF-IDF representations.

Which is a well-known limitation of using MAPE as a time series forecast accuracy metric?

Answer: MAPE is undefined when actual values equal zero and penalizes over-forecasts more than under-forecasts

MAPE involves dividing by actual values, so it is undefined at zero; it also treats positive and negative errors asymmetrically, over-penalizing forecasts that exceed actual values.

Which statement best describes the concept of 'cohesion' in cluster evaluation?

Answer: How similar points within the same cluster are to each other

Cohesion measures intra-cluster compactness — high cohesion means points within a cluster are tightly grouped and similar to one another.

What does SQL stand for?

Answer: Structured Query Language

SQL stands for Structured Query Language, used to manage and query relational databases.