1What is the primary concept behind Transfer Learning in the context of Question Answering (QA)?
A.Using hard-coded rules to extract answers from text
B.Training a model from scratch on a small QA dataset
C.Using a model pre-trained on a large corpus and fine-tuning it on a QA dataset
D.Translating questions from one language to another before answering
Correct Answer: Using a model pre-trained on a large corpus and fine-tuning it on a QA dataset
Explanation:
Transfer learning involves taking knowledge gained from solving one problem (pre-training on a large corpus) and applying it to a different but related problem (fine-tuning on specific QA data).
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2Which of the following is considered a State-Of-The-Art (SOTA) approach for Natural Language Processing tasks like Question Answering?
A.Hidden Markov Models
B.Naive Bayes Classifiers
C.Transformer-based models
D.Support Vector Machines
Correct Answer: Transformer-based models
Explanation:
Transformer-based models, such as BERT, T5, and GPT, currently achieve State-Of-The-Art results in most NLP tasks, including Question Answering.
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3In the context of BERT, what does the acronym stand for?
A.Basic Entity Recognition Technique
B.Bidirectional Encoder Representations from Transformers
C.Bigram Encoding for Robust Text
D.Binary Encoded Recurrent Transformers
Correct Answer: Bidirectional Encoder Representations from Transformers
Explanation:
BERT stands for Bidirectional Encoder Representations from Transformers, highlighting its architecture and bidirectional nature.
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4How does BERT typically approach the Question Answering task (specifically Extractive QA)?
A.It generates new text to answer the question
B.It predicts the start and end token indices of the answer span within the context passage
C.It translates the question into a database query
D.It retrieves a whole document that might contain the answer
Correct Answer: It predicts the start and end token indices of the answer span within the context passage
Explanation:
For extractive QA, BERT is trained to identify the specific span of text in the provided passage that answers the question by predicting the start and end positions.
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5What pre-training objective allows BERT to understand the relationship between two sentences, which is useful for QA contexts?
A.Next Sentence Prediction (NSP)
B.Sequence-to-Sequence generation
C.Locality Sensitive Hashing
D.Masked Language Modeling (MLM)
Correct Answer: Next Sentence Prediction (NSP)
Explanation:
Next Sentence Prediction (NSP) trains BERT to predict whether a second sentence follows the first, helping the model understand context and relationships between question and passage.
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6T5 distinguishes itself from BERT by using which unifying framework for all NLP tasks?
A.Text-to-Text
B.Regression-Analysis
C.Token-Classification
D.Image-to-Text
Correct Answer: Text-to-Text
Explanation:
T5 (Text-to-Text Transfer Transformer) converts every NLP problem, including translation, classification, and QA, into a text-to-text format where both input and output are text strings.
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7In the T5 model, how is a specific task (like Question Answering) triggered?
A.By using a separate encoder for each task
B.By manually adjusting the learning rate
C.By using a specific task prefix in the input text
D.By changing the model architecture
Correct Answer: By using a specific task prefix in the input text
Explanation:
T5 uses prefixes like 'question:', 'translate English to German:', or 'summarize:' added to the input to tell the model which task to perform.
T5 uses the standard Encoder-Decoder Transformer architecture, unlike BERT (Encoder-only) or GPT (Decoder-only).
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9When building a Chatbot, what is the 'Context Window' challenge?
A.The model cannot understand multiple languages
B.The model cannot process images
C.The model generates text too slowly
D.The model has a limit on the amount of previous conversation history it can remember
Correct Answer: The model has a limit on the amount of previous conversation history it can remember
Explanation:
Transformers have a fixed maximum sequence length (context window). If a conversation exceeds this, the model 'forgets' the earliest parts of the dialogue.
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10What is 'Hallucination' in the context of Chatbots and QA models?
A.The model crashing due to memory overflow
B.The model generating factually incorrect information confidently
C.The model failing to produce any output
D.The model copying the user's input exactly
Correct Answer: The model generating factually incorrect information confidently
Explanation:
Hallucination refers to the phenomenon where a generative model produces text that is fluent and confident but factually wrong or nonsensical.
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11Which of the following is a major computational challenge faced by standard Transformer models like BERT?
A.Quadratic memory and time complexity relative to sequence length
B.Inability to handle numerical data
C.Requirement of labeled data only
D.Linear dependence on sequence length
Correct Answer: Quadratic memory and time complexity relative to sequence length
Explanation:
The self-attention mechanism in standard Transformers requires O(N^2) time and memory, making it expensive to process very long sequences.
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12The Reformer model is designed to address which specific limitation of the Transformer?
A.Efficiency and memory usage on long sequences
B.The need for tokenization
C.Low accuracy on short sentences
D.The inability to do translation
Correct Answer: Efficiency and memory usage on long sequences
Explanation:
The Reformer is specifically engineered to handle long context windows efficiently by reducing the memory footprint and computational complexity of the attention mechanism.
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13What technique does the Reformer use to approximate the attention mechanism efficiently?
A.Recurrent connections
B.Convolutional layers
C.Locality Sensitive Hashing (LSH)
D.Global Average Pooling
Correct Answer: Locality Sensitive Hashing (LSH)
Explanation:
Reformer uses Locality Sensitive Hashing (LSH) attention to group similar vectors together, allowing it to compute attention only among relevant tokens, reducing complexity from O(N^2) to O(N log N).
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14In a Reformer model, what is the purpose of Reversible Residual Layers?
A.To allow the model to run on CPUs only
B.To increase the number of parameters without increasing size
C.To reverse the text direction for bidirectional context
D.To store activations only once, allowing recalculation during backpropagation to save memory
Correct Answer: To store activations only once, allowing recalculation during backpropagation to save memory
Explanation:
Reversible layers allow the activations of the previous layer to be computed from the next layer, meaning the model doesn't need to store all intermediate activations in memory for backpropagation.
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15Which special token is used in BERT to separate the question from the context passage?
A.[PAD]
B.[CLS]
C.[SEP]
D.[MASK]
Correct Answer: Array
Explanation:
The [SEP] token is used in BERT to distinguish between sentence A (e.g., Question) and sentence B (e.g., Context/Passage).
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16In T5's pre-training strategy, what is 'span corruption'?
A.Shuffling the order of sentences in a paragraph
B.Deleting random words and asking the model to predict the sentiment
C.Replacing spans of text with a unique sentinel token and training the model to reconstruct the missing span
D.Corrupting the embeddings with noise
Correct Answer: Replacing spans of text with a unique sentinel token and training the model to reconstruct the missing span
Explanation:
T5 is pre-trained by masking contiguous spans of text with sentinel tokens (e.g., <extra_id_0>) and asking the decoder to generate the text meant to fill those slots.
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17A Chatbot built using a Retrieval-Based model differs from a Generative model because:
A.It selects the best response from a predefined database of responses
B.It creates new sentences word-by-word
C.It uses voice recognition
D.It requires no training data
Correct Answer: It selects the best response from a predefined database of responses
Explanation:
Retrieval-based chatbots pick an existing response from a database based on similarity, whereas generative models (like T5 or GPT) construct new responses token by token.
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18What is the 'Consistency' challenge in Chatbots?
A.The bot using consistent grammar
B.The bot contradicting its own previous statements or persona
C.The bot consistently answering correctly
D.The bot replying with the same answer to every question
Correct Answer: The bot contradicting its own previous statements or persona
Explanation:
Consistency refers to the bot maintaining a stable persona (e.g., age, name) and not contradicting facts it stated earlier in the conversation.
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19Why is the SQuAD (Stanford Question Answering Dataset) important for QA models?
A.It is a database of all possible questions in English
B.It is a standardized benchmark dataset for evaluating reading comprehension and QA systems
C.It provides the code for the models
D.It is used to translate questions
Correct Answer: It is a standardized benchmark dataset for evaluating reading comprehension and QA systems
Explanation:
SQuAD is a widely used benchmark dataset consisting of questions posed on Wikipedia articles, used to train and evaluate Extractive QA models.
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20In BERT, what represents the aggregate representation of the entire sequence, often used for classification?
A.The average of all token embeddings
B.The output embedding of the [SEP] token
C.The embedding of the last token
D.The output embedding of the [CLS] token
Correct Answer: The output embedding of the [CLS] token
Explanation:
The [CLS] token is added to the start of every sequence in BERT, and its final hidden state is used as the aggregate representation for classification tasks.
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21Which of the following is a solution to the 'Blandness' problem (generic responses like 'I don't know') in generative chatbots?
A.Removing the attention mechanism
B.Training on less data
C.Adjusting the temperature or decoding strategy (e.g., Nucleus Sampling)
D.Decreasing the model size
Correct Answer: Adjusting the temperature or decoding strategy (e.g., Nucleus Sampling)
Explanation:
Beam search often leads to repetitive/bland text. Techniques like Top-K or Nucleus (Top-P) sampling, and adjusting temperature, encourage more diverse and interesting responses.
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22How does the Reformer model handle the issue of large embedding tables for vocabulary?
A.This is not a specific focus of the Reformer (it focuses on attention and depth memory)
B.It uses very small vocabulary sizes
C.It removes the vocabulary
D.It uses character-level embeddings only
Correct Answer: This is not a specific focus of the Reformer (it focuses on attention and depth memory)
Explanation:
While some models use specific embedding tricks, the Reformer's primary innovations are LSH Attention and Reversible Layers to solve the sequence length and depth memory bottlenecks.
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23What is 'Fine-Tuning' in the context of building a QA model with BERT?
A.Updating the weights of a pre-trained BERT model using a specific QA dataset
B.Designing the neural network architecture from scratch
C.Adjusting the hyperparameters of the model manually
D.Cleaning the text data before input
Correct Answer: Updating the weights of a pre-trained BERT model using a specific QA dataset
Explanation:
Fine-tuning involves taking the pre-trained weights (which know language structure) and continuing the training process on the specific QA data to specialize the model.
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24In T5, what dataset was primarily used for pre-training?
T5 was pre-trained on the C4 dataset, a massive, cleaned version of the Common Crawl web scrape.
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25What is a major advantage of the T5 'Text-to-Text' framework over BERT's approach?
A.It requires no GPU
B.It is faster to train
C.It uses fewer parameters
D.It allows the same model and loss function to be used for generation, translation, and classification
Correct Answer: It allows the same model and loss function to be used for generation, translation, and classification
Explanation:
By treating everything as text generation, T5 simplifies the modeling pipeline, allowing a single model architecture and objective to handle diverse tasks without task-specific heads.
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26When training a chatbot, what is 'Teacher Forcing'?
A.Forcing the model to stop training early
B.Using the ground-truth previous token as input during training instead of the model's own generated output
C.A human teacher corrects the bot's answers
D.Using a larger model to teach a smaller model
Correct Answer: Using the ground-truth previous token as input during training instead of the model's own generated output
Explanation:
Teacher forcing speeds up training by feeding the correct previous token to the decoder at each step, rather than the token the model actually predicted.
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27Which challenge for Transformer models relates to the maximum number of tokens it can process at once?
A.Bias variance tradeoff
B.Vanishing Gradient
C.Sequence Length Limit
D.Overfitting
Correct Answer: Sequence Length Limit
Explanation:
Standard Transformers (like BERT) usually have a hard limit (e.g., 512 tokens) due to the positional encoding design and the quadratic cost of attention.
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28In the Reformer, what happens if two vectors fall into the same hash bucket during LSH?
A.They are moved to a different layer
B.They are merged into one vector
C.They are deleted
D.They are considered for attention calculation with each other
Correct Answer: They are considered for attention calculation with each other
Explanation:
LSH sorts vectors into buckets based on similarity. Only vectors within the same bucket (or adjacent chunks) attend to each other, approximating the full attention mechanism.
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29What is 'Abstractive' Question Answering?
A.Answering yes/no questions only
B.Generating an answer that may contain words not present in the context passage
C.Ignoring the context passage
D.Highlighting the answer in the text
Correct Answer: Generating an answer that may contain words not present in the context passage
Explanation:
Abstractive QA involves understanding the context and generating a summary or answer in natural language, rephrasing content rather than just extracting a direct span.
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30Which evaluation metric is commonly used for measuring the overlap between a chatbot's generated response and a reference response?
A.BLEU or ROUGE
B.Mean Squared Error
C.Accuracy
D.F1-Score (for classification)
Correct Answer: BLEU or ROUGE
Explanation:
BLEU and ROUGE are metrics based on n-gram overlap between the generated text and reference text, commonly used in translation and summarization/chatbots.
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31Does BERT process text sequentially from left-to-right?
A.Yes, strictly left-to-right
B.Yes, but also right-to-left in separate layers
C.No, it processes the entire sequence simultaneously (bidirectionally)
D.No, it processes random words first
Correct Answer: No, it processes the entire sequence simultaneously (bidirectionally)
Explanation:
Unlike RNNs or GPT (left-to-right), BERT's Transformer encoder reads the entire sequence at once, allowing it to learn context from both sides of a token.
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32What is the 'Safety' challenge in open-domain chatbots?
A.Ensuring the model saves data securely
B.Preventing the model from being deleted
C.Preventing users from hacking the server
D.Preventing the generation of toxic, biased, or offensive content
Correct Answer: Preventing the generation of toxic, biased, or offensive content
Explanation:
Since chatbots are trained on internet data, a major challenge is ensuring they do not output hate speech, bias, or harmful instructions.
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33How does the Reformer save memory regarding the 'Q, K, V' matrices in Attention?
A.It eliminates the Value matrix
B.It uses shared Query (Q) and Key (K) spaces
C.It compresses them using JPEG
D.It stores them on the hard drive
Correct Answer: It uses shared Query (Q) and Key (K) spaces
Explanation:
The Reformer simplifies attention by assuming Q = K (shared keys and queries), reducing the number of matrices needed and facilitating the LSH scheme.
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34When using BERT for QA, what does the model output for every token in the passage?
A.A probability score for being the 'Start' and 'End' of the answer
B.A probability of being the next word
C.A sentiment score
D.A translation of the token
Correct Answer: A probability score for being the 'Start' and 'End' of the answer
Explanation:
BERT outputs two logits for each token: one representing the likelihood of it being the start of the answer span, and one for being the end.
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35Which model would be most appropriate for summarising a very long book into a short paragraph?
A.Standard BERT (limit 512 tokens)
B.A simple RNN
C.Naive Bayes
D.Reformer (or Longformer)
Correct Answer: Reformer (or Longformer)
Explanation:
Because a book far exceeds the token limit of standard transformers, a Reformer (which handles long sequences efficiently) is the most appropriate choice.
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36In the context of T5, what does 'Transfer Learning' specifically refer to?
A.Transferring files between computers
B.Transferring the weights from a pre-trained general model to a specific downstream task
C.Transferring data from training set to test set
D.Transferring the style of one author to another
Correct Answer: Transferring the weights from a pre-trained general model to a specific downstream task
Explanation:
It refers to the methodology of pre-training on a generic task (unsupervised) and then fine-tuning on a specific task (supervised) like QA.
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37What is a 'Persona-based' Chatbot?
A.A bot that changes personality every turn
B.A bot that asks for personal information
C.A bot used only for personnel management
D.A bot conditioned on a specific profile (e.g., 'I am a doctor') to improve consistency
Correct Answer: A bot conditioned on a specific profile (e.g., 'I am a doctor') to improve consistency
Explanation:
To solve consistency issues, bots are often conditioned on a 'persona' profile provided in the input context.
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38Why is 'Masked Language Modeling' (MLM) harder than standard left-to-right language modeling?
A.It uses images
B.The model must deduce the missing word based on bidirectional context rather than just previous words
C.It requires more labeled data
D.It isn't; it is easier
Correct Answer: The model must deduce the missing word based on bidirectional context rather than just previous words
Explanation:
MLM requires the model to understand the full context (words before and after) to fill in the blank, creating deeper contextual representations.
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39What is the typical size of the vocabulary in models like BERT or T5?
A.100 words
B.Around 30,000 to 50,000 tokens (WordPieces/SentencePieces)
C.1 Million words
D.26 letters
Correct Answer: Around 30,000 to 50,000 tokens (WordPieces/SentencePieces)
Explanation:
These models use sub-word tokenization algorithms (like WordPiece for BERT) resulting in vocabulary sizes usually between 30k and 50k.
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40In a Chatbot, 'Multi-turn' capability means:
A.The bot can speak multiple languages
B.The bot spins around
C.The bot can handle a conversation with back-and-forth exchanges while maintaining context
D.The bot can answer multiple questions at once
Correct Answer: The bot can handle a conversation with back-and-forth exchanges while maintaining context
Explanation:
Multi-turn dialogue systems maintain state across several user-system exchanges, unlike single-turn systems (like simple FAQs).
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41What is the primary trade-off when using a Reformer model with Reversible Layers?
A.Lower accuracy for higher memory
B.Higher memory usage for faster speed
C.It can only process numbers
D.Slightly higher computational cost (re-computing) for significantly lower memory usage
Reversible layers require re-computing the forward pass during the backward pass. This trades a small increase in compute time for a massive reduction in memory.
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42T5 typically uses which type of positional encoding?
A.Absolute sinusoidal embeddings
B.Relative position embeddings
C.GPS coordinates
D.No positional encoding
Correct Answer: Relative position embeddings
Explanation:
T5 uses relative position embeddings, where the encoding depends on the offset between the key and query, rather than their absolute position in the sequence.
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43Which of these is NOT a standard challenge for Transformers?
A.Inability to handle sequential data
B.Interpretability (Black box nature)
C.Data hunger (need large datasets)
D.Computational cost (GPU requirements)
Correct Answer: Inability to handle sequential data
Explanation:
Transformers are explicitly designed to handle sequential data (text). The other options are valid challenges.
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44For a Chatbot, 'Slot Filling' refers to:
A.The time slot when the bot is active
B.Putting coins in a machine
C.Extracting specific parameters (e.g., date, time, location) from user input
D.Filling the memory with data
Correct Answer: Extracting specific parameters (e.g., date, time, location) from user input
Explanation:
In task-oriented chatbots, slot filling is the process of identifying specific details required to fulfill a user's intent (e.g., extracting 'tomorrow' for a 'Date' slot).
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45The 'Chunking' strategy in Reformer helps in:
A.Breaking words into letters
B.Grouping users into chunks
C.Processing long sequences by breaking them into fixed-size chunks to apply LSH attention
D.Deleting parts of the sentence
Correct Answer: Processing long sequences by breaking them into fixed-size chunks to apply LSH attention
Explanation:
To make LSH efficient, the Reformer chunks the sequence and sorts vectors within/across chunks to compute attention locally.
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46Which model introduced the 'Masked Language Model' concept?
A.LSTM
B.BERT
C.Reformer
D.T5
Correct Answer: BERT
Explanation:
While the concept existed in literature (Cloze task), BERT popularized Masked Language Modeling (MLM) as the core pre-training objective for Transformers.
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47When fine-tuning T5 for QA, the target output is:
A.A vector representation
B.A '1' or '0' (Binary classification)
C.The raw text string of the answer
D.The index of the start and end words
Correct Answer: The raw text string of the answer
Explanation:
Since T5 is text-to-text, the target label for QA is simply the text of the correct answer.
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48Why might a Reformer be less suitable than BERT for short-sequence tasks?
A.Reformer cannot handle text
B.Reformer has low accuracy
C.The overhead of LSH and reversible layers adds complexity not needed for short sequences
D.Reformer is only for images
Correct Answer: The overhead of LSH and reversible layers adds complexity not needed for short sequences
Explanation:
Reformer's optimizations (LSH, Reversibility) are designed for long sequences. For short sequences, standard Attention is efficient enough, and Reformer might introduce unnecessary overhead.
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49What is 'Zero-Shot' learning in the context of QA models?
A.The model answering questions without any specific fine-tuning on that QA dataset
B.The model training with zero data
C.The model failing 0 times
D.The model taking zero seconds to reply
Correct Answer: The model answering questions without any specific fine-tuning on that QA dataset
Explanation:
Zero-shot learning refers to a pre-trained model performing a task (like QA) without having seen any explicit examples of that task during training/fine-tuning.
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50In Chatbot development, what is the role of the 'Temperature' parameter during generation?
A.It sets the mood of the bot
B.It controls the heat of the GPU
C.It determines the length of the sentence
D.It controls the randomness of predictions (Low = deterministic, High = creative/random)
Correct Answer: It controls the randomness of predictions (Low = deterministic, High = creative/random)
Explanation:
Temperature scales the logits before the softmax. Lower temperature makes the distribution sharper (more confident/repetitive), while higher temperature flattens it (more diverse/random).