AI stands for Artificial Intelligence, the simulation of human intelligence by machines.
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2Which of the following best describes Artificial Intelligence?
definition and scope of AI
Easy
A.A type of computer network cable
B.A method for building physical hardware only
C.Machines performing tasks that normally require human intelligence
D.A tool used exclusively for printing documents
Correct Answer: Machines performing tasks that normally require human intelligence
Explanation:
AI enables machines to perform tasks such as reasoning, learning, and decision-making that typically need human intelligence.
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3The term "Artificial Intelligence" was first coined at a 1956 conference held at which university?
history and evolution of AI
Easy
A.Cambridge
B.Dartmouth
C.Stanford
D.Oxford
Correct Answer: Dartmouth
Explanation:
The term was introduced at the Dartmouth Conference in 1956, widely regarded as the birth of AI as a field.
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4Which test was proposed to check whether a machine can exhibit intelligent behavior similar to a human?
history and evolution of AI
Easy
A.Logic Test
B.Turing Test
C.Boolean Test
D.Binary Test
Correct Answer: Turing Test
Explanation:
The Turing Test, proposed by Alan Turing, checks if a machine's responses are indistinguishable from a human's.
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5Machine Learning is a subset of which broader field?
introduction to machine learning
Easy
A.Computer Networking
B.Artificial Intelligence
C.Database Administration
D.Web Design
Correct Answer: Artificial Intelligence
Explanation:
Machine Learning is a branch of AI where systems learn patterns from data instead of being explicitly programmed.
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6What is the main idea behind Machine Learning?
introduction to machine learning
Easy
A.Systems replace all computer hardware
B.Systems learn from data and improve over time
C.Systems only follow fixed rules forever
D.Systems print reports automatically
Correct Answer: Systems learn from data and improve over time
Explanation:
Machine Learning allows systems to learn from data and improve their performance without being explicitly reprogrammed.
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7Which type of machine learning uses labeled data for training?
introduction to machine learning
Easy
A.Reinforcement learning
B.Reactive learning
C.Unsupervised learning
D.Supervised learning
Correct Answer: Supervised learning
Explanation:
Supervised learning trains a model on labeled data, where the correct output is provided for each input.
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8Artificial neural networks are inspired by which biological structure?
neural networks
Easy
A.The human brain
B.The digestive system
C.The human heart
D.The skeletal system
Correct Answer: The human brain
Explanation:
Neural networks are modeled after the interconnected neurons of the human brain.
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9What is the basic unit of a neural network called?
neural networks
Easy
A.Cluster
B.Register
C.Pixel
D.Neuron (node)
Correct Answer: Neuron (node)
Explanation:
The basic processing unit of a neural network is a neuron, also called a node.
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10What does NLP stand for in the context of AI?
natural language processing
Easy
A.Natural Language Processing
B.New Logic Programming
C.Network Layer Protocol
D.Numerical Linear Processing
Correct Answer: Natural Language Processing
Explanation:
NLP stands for Natural Language Processing, which enables computers to understand and generate human language.
Incorrect! Try again.
11Which of the following is a common application of Natural Language Processing?
natural language processing
Easy
A.Chatbots and language translation
B.Cooling computer hardware
C.Charging batteries
D.Cutting metal sheets
Correct Answer: Chatbots and language translation
Explanation:
NLP powers applications like chatbots, language translation, and speech recognition that deal with human language.
Incorrect! Try again.
12What does Generative AI primarily do?
generative AI
Easy
A.Cools down servers
B.Measures network speed
C.Creates new content such as text, images, or audio
D.Deletes files automatically
Correct Answer: Creates new content such as text, images, or audio
Explanation:
Generative AI generates new content, such as text, images, music, or code, based on patterns learned from data.
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13Which of the following is an example of a Generative AI tool?
generative AI
Easy
A.Windows Calculator
B.ChatGPT
C.Microsoft Excel
D.WinRAR
Correct Answer: ChatGPT
Explanation:
ChatGPT is a generative AI tool that produces human-like text responses.
Incorrect! Try again.
14Data Science mainly focuses on extracting what from data?
Data science: definition and importance
Easy
A.Sound waves
B.Physical materials
C.Useful insights and knowledge
D.Electric power
Correct Answer: Useful insights and knowledge
Explanation:
Data Science combines statistics, programming, and domain knowledge to extract useful insights from data.
Incorrect! Try again.
15Why is Data Science important for organizations?
Data science: definition and importance
Easy
A.It helps make better data-driven decisions
B.It replaces office furniture
C.It slows down computer processing
D.It removes the need for electricity
Correct Answer: It helps make better data-driven decisions
Explanation:
Data Science enables organizations to make informed, data-driven decisions and discover trends.
Incorrect! Try again.
16Which of the following is one of the well-known "V"s used to describe Big Data?
big data
Easy
A.Velocity of light
B.Vision
C.Volume
D.Voltage
Correct Answer: Volume
Explanation:
Big Data is often described by the 3 Vs: Volume, Velocity, and Variety. Volume refers to the huge amount of data.
Incorrect! Try again.
17The term Big Data generally refers to datasets that are:
big data
Easy
A.Only stored on paper
B.Made only of images
C.Too large and complex for traditional tools to handle
D.Always smaller than one kilobyte
Correct Answer: Too large and complex for traditional tools to handle
Explanation:
Big Data refers to extremely large and complex datasets that traditional data processing tools cannot handle efficiently.
Incorrect! Try again.
18Which of the following is a common method of collecting data?
Data collection methods
Easy
A.Formatting a hard disk
B.Surveys and questionnaires
C.Painting walls
D.Watering plants
Correct Answer: Surveys and questionnaires
Explanation:
Surveys and questionnaires are widely used methods for collecting data directly from respondents.
Incorrect! Try again.
19Data collected directly by a researcher for a specific purpose is called:
primary vs. secondary data
Easy
A.Secondary data
B.Tertiary data
C.Primary data
D.Backup data
Correct Answer: Primary data
Explanation:
Primary data is original data collected firsthand by the researcher for a specific purpose.
Incorrect! Try again.
20Data obtained from already existing sources like books or reports is called:
primary vs. secondary data
Easy
A.Live data
B.Secondary data
C.Raw data
D.Primary data
Correct Answer: Secondary data
Explanation:
Secondary data is data that was previously collected by someone else and reused, such as reports, books, or online sources.
Incorrect! Try again.
21A system that plays chess by evaluating millions of board positions but cannot recognize a spoken word is best described as an example of which type of AI?
definition and scope of AI
Medium
A.Super AI
B.General (Strong) AI
C.Narrow (Weak) AI
D.Reactive-free AI
Correct Answer: Narrow (Weak) AI
Explanation:
Narrow AI is designed to perform a single specialized task well (like chess) and cannot transfer that ability to unrelated tasks such as speech recognition.
Incorrect! Try again.
22The period during which AI research funding and interest sharply declined due to unmet expectations is commonly referred to as the:
history and evolution of AI
Medium
A.AI Boom
B.AI Winter
C.Turing Era
D.Expert Freeze
Correct Answer: AI Winter
Explanation:
An "AI Winter" describes phases of reduced funding and pessimism that followed periods of overpromised results in AI research.
Incorrect! Try again.
23Which test, proposed in 1950, evaluates a machine's ability to exhibit intelligent behavior indistinguishable from a human?
history and evolution of AI
Medium
A.The Boolean Test
B.The Bayes Test
C.The Dartmouth Test
D.The Turing Test
Correct Answer: The Turing Test
Explanation:
Alan Turing proposed the Turing Test, where a machine passes if a human evaluator cannot reliably tell it apart from a human based on conversation.
Incorrect! Try again.
24A model is trained on emails labeled as "spam" or "not spam" so it can classify new emails. This is an example of:
introduction to machine learning
Medium
A.Supervised learning
B.Reinforcement learning
C.Unsupervised learning
D.Transfer clustering
Correct Answer: Supervised learning
Explanation:
Supervised learning uses labeled data (spam/not spam) to learn a mapping from inputs to known outputs, enabling classification of new data.
Incorrect! Try again.
25A customer segmentation task groups shoppers by purchasing behavior without any predefined labels. Which learning type applies?
introduction to machine learning
Medium
A.Reinforcement learning
B.Unsupervised learning
C.Semi-labeled regression
D.Supervised learning
Correct Answer: Unsupervised learning
Explanation:
Unsupervised learning finds hidden patterns or clusters in unlabeled data, which is exactly what customer segmentation does.
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26A model performs very well on training data but poorly on new, unseen data. This problem is called:
introduction to machine learning
Medium
A.Overfitting
B.Regularization
C.Underfitting
D.Normalization
Correct Answer: Overfitting
Explanation:
Overfitting occurs when a model memorizes training data, including noise, and fails to generalize to new data.
Incorrect! Try again.
27In an artificial neural network, what is the primary purpose of an activation function?
neural networks
Medium
A.To label the output classes
B.To introduce non-linearity into the model
C.To collect raw input data
D.To store the training dataset
Correct Answer: To introduce non-linearity into the model
Explanation:
Activation functions add non-linearity, allowing neural networks to learn complex patterns that a purely linear model could not capture.
Incorrect! Try again.
28A neural network that contains many hidden layers between the input and output layers is commonly called a:
neural networks
Medium
A.Deep neural network
B.Linear regressor
C.Decision tree
D.Shallow perceptron
Correct Answer: Deep neural network
Explanation:
Networks with multiple hidden layers are termed "deep" networks, and their use is the basis of deep learning.
Incorrect! Try again.
29Which component of a neuron controls the strength of the connection between two nodes and is adjusted during training?
neural networks
Medium
A.Label
B.Token
C.Epoch
D.Weight
Correct Answer: Weight
Explanation:
Weights determine how strongly one neuron's output influences another; training adjusts weights to minimize error.
Incorrect! Try again.
30Breaking the sentence "AI is useful" into the individual units ["AI", "is", "useful"] is an NLP step known as:
natural language processing
Medium
A.Normalization
B.Tokenization
C.Vectorization scoring
D.Compilation
Correct Answer: Tokenization
Explanation:
Tokenization splits text into smaller units (tokens) such as words, which is a fundamental preprocessing step in NLP.
Incorrect! Try again.
31An application that analyzes product reviews to decide whether each is positive or negative is performing:
natural language processing
Medium
A.Sentiment analysis
B.Image segmentation
C.Speech synthesis
D.Data compression
Correct Answer: Sentiment analysis
Explanation:
Sentiment analysis is an NLP task that classifies text according to the emotional tone or opinion it expresses.
Incorrect! Try again.
32Which of the following best distinguishes generative AI from traditional discriminative models?
generative AI
Medium
A.It creates new content rather than only classifying existing data
B.It requires no training data at all
C.It cannot process text or images
D.It only sorts data into fixed categories
Correct Answer: It creates new content rather than only classifying existing data
Explanation:
Generative AI produces new outputs (text, images, audio), whereas discriminative models mainly classify or predict labels for existing inputs.
Incorrect! Try again.
33When a language model produces confident but factually incorrect information, this behavior is commonly called:
generative AI
Medium
A.Overfitting
B.Tokenization
C.Backpropagation
D.Hallucination
Correct Answer: Hallucination
Explanation:
"Hallucination" refers to a generative model producing plausible-sounding but false or fabricated information.
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34Data science is best described as an interdisciplinary field that primarily combines:
Data science: definition and importance
Medium
A.Only spreadsheet formatting and typing
B.Statistics, computer science, and domain knowledge
C.Graphic design and video editing
D.Hardware repair and networking cables
Correct Answer: Statistics, computer science, and domain knowledge
Explanation:
Data science blends statistical methods, computational tools, and subject-matter expertise to extract insights from data.
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35In the classic "3 Vs" of big data, the term Velocity refers to:
big data
Medium
A.The number of different data formats
B.The total size of stored data
C.The speed at which data is generated and processed
D.The accuracy of the data values
Correct Answer: The speed at which data is generated and processed
Explanation:
Velocity captures how fast data is created and must be handled; Volume is size and Variety is format diversity.
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36A dataset containing tweets, images, videos, and sensor logs together demonstrates which characteristic of big data?
big data
Medium
A.Veracity
B.Volume
C.Velocity
D.Variety
Correct Answer: Variety
Explanation:
Variety refers to the many different types and formats of data (structured, unstructured, and semi-structured) being combined.
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37A researcher uses an online questionnaire to gather opinions directly from users for a new study. This is an example of:
Data collection methods
Medium
A.Data transformation
B.Data cleaning
C.Primary data collection through a survey
D.Secondary data from a published report
Correct Answer: Primary data collection through a survey
Explanation:
Collecting data firsthand for a specific purpose (via survey) is primary data collection.
Incorrect! Try again.
38Which scenario clearly uses secondary data?
primary vs. secondary data
Medium
A.Running your own experiment and recording results
B.Analyzing census figures published by a government agency
C.Observing traffic and manually counting cars
D.Interviewing customers in person for feedback
Correct Answer: Analyzing census figures published by a government agency
Explanation:
Secondary data is collected by someone else for another purpose and reused; published census figures fit this definition.
Incorrect! Try again.
39A dataset column for "age" contains the value 250 and several blank cells. Which two data cleaning issues are present?
basics of data cleaning and transformation
Medium
A.Overfitting and underfitting
B.Tokenization and stemming
C.Encryption and compression
D.Outliers and missing values
Correct Answer: Outliers and missing values
Explanation:
An age of 250 is an outlier/invalid value, and blank cells represent missing values, both are common cleaning problems.
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40Converting all values in a numeric feature to a common to range is a transformation step known as:
basics of data cleaning and transformation
Medium
A.Deduplication
B.Tokenization
C.Imputation
D.Normalization
Correct Answer: Normalization
Explanation:
Normalization rescales numeric values into a common range (often to ) so features are comparable and models train better.
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41A system uses a large lookup table to respond to every possible input with a pre-defined output, showing no capacity to generalize to unseen inputs. Under the standard definition of AI as systems that can learn, reason, and adapt, how should this system be classified?
definition and scope of AI
Hard
A.It is an example of artificial general intelligence
B.It is a machine learning system because it maps inputs to outputs
C.It is a strong AI because it can respond to any input correctly
D.It is not genuinely intelligent because it lacks generalization and adaptation, relying purely on stored rules
Correct Answer: It is not genuinely intelligent because it lacks generalization and adaptation, relying purely on stored rules
Explanation:
AI implies the ability to generalize, reason, or adapt to novel situations. A fixed lookup table cannot handle unseen inputs, so it is rule-based automation, not intelligence in the meaningful sense.
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42The period roughly from the 1970s to 1980s and again in the late 1980s is often called an 'AI winter.' What was the primary cause of these downturns?
history and evolution of AI
Hard
A.The invention of the transistor made all prior AI obsolete
B.A collapse in funding and interest after AI systems failed to meet inflated expectations and hit computational and data limits
C.A total ban on AI research imposed by governments worldwide
D.The discovery that neural networks could never be trained
Correct Answer: A collapse in funding and interest after AI systems failed to meet inflated expectations and hit computational and data limits
Explanation:
AI winters resulted from overhyped promises that could not be delivered, combined with limited compute and data, leading to reduced funding and pessimism.
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43A model achieves 99% accuracy on training data but only 62% on test data. Which combination of description and remedy is most accurate?
introduction to machine learning
Hard
A.Overfitting; apply regularization, gather more data, or reduce model complexity
B.Underfitting; increase model complexity substantially
C.High bias; remove regularization entirely
D.Data leakage; the labels are missing from training
Correct Answer: Overfitting; apply regularization, gather more data, or reduce model complexity
Explanation:
A large gap between high training accuracy and low test accuracy signals overfitting (high variance). Regularization, more data, or simpler models reduce this gap.
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44You are given a dataset with 10,000 samples where only 50 belong to the positive class (fraud). A classifier predicts 'not fraud' for every sample. What accuracy does it achieve, and why is accuracy misleading here?
introduction to machine learning
Hard
A. accuracy, but it is misleading because the classifier never detects the minority class
B. accuracy, which reflects perfect fraud detection
C. accuracy, which is acceptable for imbalanced data
D. accuracy, because the classes are balanced
Correct Answer: accuracy, but it is misleading because the classifier never detects the minority class
Explanation:
With 9,950 of 10,000 correct by always predicting the majority class, accuracy is . On imbalanced data, precision, recall, or F1 are more informative than accuracy.
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45In a deep feedforward network using sigmoid activations, gradients become extremely small in early layers during backpropagation, slowing learning. What is this problem and a common mitigation?
neural networks
Hard
A.Vanishing gradients; use ReLU activations and normalized initialization to preserve gradient magnitude
B.Overfitting; increase the learning rate
C.Underfitting; remove all activation functions
D.Exploding gradients; add more sigmoid layers
Correct Answer: Vanishing gradients; use ReLU activations and normalized initialization to preserve gradient magnitude
Explanation:
Sigmoid derivatives are at most , so repeated multiplication shrinks gradients across layers. ReLU and careful weight initialization help gradients flow through deep networks.
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46Why does a multilayer neural network require non-linear activation functions between layers?
neural networks
Hard
A.They are only needed in the output layer to produce probabilities
B.They make the network train faster by reducing the number of weights
C.They guarantee the network will never overfit the training data
D.Without them, a stack of linear layers collapses into a single equivalent linear transformation, unable to model non-linear relationships
Correct Answer: Without them, a stack of linear layers collapses into a single equivalent linear transformation, unable to model non-linear relationships
Explanation:
A composition of linear functions is still linear. Non-linear activations let the network approximate complex, non-linear decision boundaries.
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47A traditional bag-of-words model classifies the sentences 'The service was good, not bad' and 'The service was bad, not good' identically. What core NLP limitation does this expose?
natural language processing
Hard
A.It requires the sentences to be translated first
B.It cannot handle words longer than five characters
C.It ignores word order and syntactic context, so it cannot capture meaning that depends on sequence
D.It only works on numeric data, not text
Correct Answer: It ignores word order and syntactic context, so it cannot capture meaning that depends on sequence
Explanation:
Bag-of-words treats text as an unordered set of tokens, so both sentences yield the same feature vector despite opposite meanings. Sequence models or transformers address this.
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48In word embeddings such as Word2Vec, the relationship can be observed. What property of the embedding space does this demonstrate?
natural language processing
Hard
A.Semantic and syntactic relationships are encoded as consistent linear directions in vector space
B.Embeddings only capture spelling similarity, not meaning
C.The model has memorized every sentence in its training corpus
D.Words are stored as unique integer IDs with no relationships
Correct Answer: Semantic and syntactic relationships are encoded as consistent linear directions in vector space
Explanation:
Vector arithmetic works because embeddings place related concepts along consistent directions, capturing analogies like gender or royalty as vector offsets.
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49A large language model confidently produces a fabricated citation to a non-existent research paper. What is this phenomenon, and what is its root cause?
generative AI
Hard
A.Overfitting; the model memorized the wrong citation
B.Data leakage; the citation appeared in the test set
C.Hallucination; the model predicts statistically plausible token sequences without any grounded verification of factual truth
D.Gradient explosion during text generation
Correct Answer: Hallucination; the model predicts statistically plausible token sequences without any grounded verification of factual truth
Explanation:
Generative models optimize for likely next tokens, not truth. They can produce fluent, plausible-sounding but false content, called hallucination.
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50Which statement best distinguishes discriminative models from generative models?
generative AI
Hard
A.Generative models cannot be used for any classification task
B.Discriminative models learn to separate classes, while generative models learn or to produce new samples
C.Discriminative models generate new data, while generative models only classify
D.Both learn identical distributions but differ only in speed
Correct Answer: Discriminative models learn to separate classes, while generative models learn or to produce new samples
Explanation:
Discriminative models estimate the conditional probability of labels given inputs, while generative models model the data distribution itself, enabling generation of new samples.
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51A team builds a highly accurate churn-prediction model but never translates it into any business action or intervention. From a data science value perspective, what is the key failure?
Data science: definition and importance
Hard
A.The model accuracy was too high to be trusted
B.The team used too little data to train the model
C.Insights were never operationalized into decisions, so the analytics produced no actionable value
D.Data science requires no connection to business outcomes
Correct Answer: Insights were never operationalized into decisions, so the analytics produced no actionable value
Explanation:
The purpose of data science is to drive decisions and value. A model that is never acted upon delivers no business impact regardless of its accuracy.
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52A company streams sensor readings arriving in inconsistent formats at millions of events per second and needs real-time analysis. Which combination of the 'V's of big data is MOST directly stressed?
big data
Hard
A.Veracity and value only, since the data is trustworthy
B.Only volume, since the total size is large
C.None of the V's apply to streaming data
D.Velocity and variety, since data arrives fast and in heterogeneous formats
Correct Answer: Velocity and variety, since data arrives fast and in heterogeneous formats
Explanation:
High-speed arrival stresses velocity, while inconsistent formats stress variety. Volume may also be high, but the described challenges center on speed and format diversity.
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53A researcher conducts an online voluntary survey and generalizes the results to the entire national population. What is the most serious methodological flaw?
Data collection methods
Hard
A.Surveys always produce perfectly random samples
B.Online surveys guarantee causal conclusions
C.Selection bias, because voluntary online respondents are not representative of the whole population
D.The sample is too large to analyze correctly
Correct Answer: Selection bias, because voluntary online respondents are not representative of the whole population
Explanation:
Self-selected online respondents differ systematically from the general population (access, motivation, demographics), so results cannot be generalized without correcting for this bias.
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54An analyst reuses a government census dataset collected years ago for a new study on current housing trends. Which limitation of secondary data is MOST relevant?
primary vs. secondary data
Hard
A.Secondary data is always more expensive than primary data
B.The analyst automatically owns the copyright to the census data
C.Secondary data cannot be used in any research
D.The data may be outdated and was collected for a different purpose, reducing relevance to the current question
Correct Answer: The data may be outdated and was collected for a different purpose, reducing relevance to the current question
Explanation:
Secondary data is cheaper and faster but was gathered for other purposes and may be dated, so it can lack fit and currency for the new research question.
Incorrect! Try again.
55A startup interviews 200 of its own customers directly to understand product satisfaction. A competitor's published market report is also consulted. Which classification is correct?
primary vs. secondary data
Hard
A.Both are secondary data because they were analyzed later
B.Both sources are primary data because both concern the market
C.The interviews are primary data; the market report is secondary data
D.The interviews are secondary data; the report is primary data
Correct Answer: The interviews are primary data; the market report is secondary data
Explanation:
Primary data is collected firsthand for the specific purpose (the interviews). Secondary data is compiled by others for other purposes (the published report).
Incorrect! Try again.
56A dataset has a numeric 'income' column with 15% missing values that are missing not at random (higher earners tend not to report). Simply replacing them with the column mean is risky because:
basics of data cleaning and transformation
Hard
A.The mean cannot be computed when values are missing
B.Mean imputation ignores the systematic pattern of missingness and biases the distribution toward the center
C.Mean imputation always increases variance beyond the true value
D.Missing values can never be imputed under any circumstances
Correct Answer: Mean imputation ignores the systematic pattern of missingness and biases the distribution toward the center
Explanation:
When data is missing not at random, mean imputation distorts the true distribution and underestimates variance, introducing bias. Model-based or informed methods are preferable.
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57A feature 'age' ranges from 0 to 100 while 'salary' ranges from 0 to 200,000. A distance-based algorithm like k-NN performs poorly. What transformation directly addresses this?
basics of data cleaning and transformation
Hard
A.Feature scaling (normalization or standardization) so both features contribute comparably to distance
B.One-hot encoding both numeric columns
C.Converting salary to a categorical string
D.Removing the age column entirely
Correct Answer: Feature scaling (normalization or standardization) so both features contribute comparably to distance
Explanation:
Distance metrics are dominated by large-scale features. Scaling features to comparable ranges ensures each contributes fairly to distance computations in k-NN.
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58A retailer wants to know not just what happened and why, but what action to take to maximize revenue next quarter. Which type of analytics does this require?
introduction to data analytics
Hard
A.Predictive analytics alone, which only forecasts outcomes
B.Diagnostic analytics, which only explains past causes
C.Prescriptive analytics, which recommends actions using optimization and simulation
D.Descriptive analytics, which only summarizes past data
Correct Answer: Prescriptive analytics, which recommends actions using optimization and simulation
Explanation:
Descriptive answers 'what happened,' diagnostic 'why,' predictive 'what will happen,' and prescriptive 'what should we do.' Recommending optimal actions is prescriptive.
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59An analyst finds that ice cream sales and drowning incidents are strongly correlated and concludes ice cream causes drownings. What is the flaw, and what likely explains the correlation?
introduction to data analytics
Hard
A.Two variables can never be correlated by chance
B.The correlation coefficient was calculated incorrectly
C.Drowning must cause ice cream sales instead
D.Correlation is not causation; a confounding variable (hot weather) drives both
Correct Answer: Correlation is not causation; a confounding variable (hot weather) drives both
Explanation:
A lurking variable, warm weather, independently increases both ice cream sales and swimming (hence drownings). Correlation alone does not establish a causal link.
Incorrect! Try again.
60In k-fold cross-validation with , which statement is TRUE about how the data is used?
introduction to machine learning
Hard
A.The model is trained once on 80% and never validated on the rest
B.All 5 folds are used simultaneously as both training and test data
C.Each sample is used only for training and never for validation
D.The data is split into 5 folds; each fold serves as the validation set once while the other 4 train the model, and results are averaged
Correct Answer: The data is split into 5 folds; each fold serves as the validation set once while the other 4 train the model, and results are averaged
Explanation:
In 5-fold cross-validation, training and validation rotate across folds so every sample is validated exactly once, giving a more robust performance estimate.
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