# SEAS-8414 Chapter 8 Homework
## Blackboard Multiple-Choice Assessment: Federated Threat Intelligence Network

**Use:** Due before the next Chapter 9 class session
**Total Points:** 100
**Format:** 50 single-correct-answer multiple choice questions, 2 points each
**Audience:** Doctoral students and senior cybersecurity practitioners

This assessment is designed for Blackboard delivery. Every item is multiple choice
with exactly one correct answer. The assessment is closed book: do not use the
textbook, notes, internet search, lab files, scanners, AI tools, or outside
incident writeups while answering.

Each question includes a scenario-provenance label. That label is a citation
trail for instructors and is never required to choose the answer. Every formula,
threshold, rule, or evidence contract required to answer appears inside the stem.

Chapter boundary: answer only within Chapter 8 federated cyber analytics, privacy accounting, and robust aggregation only. Do not import capabilities
from other chapters unless the stem explicitly defines them.

---

### Question 1

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility tracks a Chapter 8 privacy budget. The rule is remaining_rounds = floor((epsilon_budget - epsilon_spent) / epsilon_per_round). The budget is 10.0, epsilon_spent is 2.1, and each additional round consumes 0.50. Which count follows?

(a) 16 rounds
(b) 20 rounds
(c) 14 rounds
(d) 15 rounds
### Question 2

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network configures Multi-Krum for a federated IoT detector. The self-contained safety condition is n >= 2f + 3, where n is the number of submitted site updates and f is the maximum Byzantine update count tolerated. Here n=11. What is the largest integer f allowed by the condition?

(a) No determinate answer can be computed from the stated rule.
(b) f = 3
(c) f = 4
(d) f = 5
### Question 3

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority audits a TransformerIDS model. The stem defines d_k = d_model / attention_heads and scaled dot-product attention divides the dot product by sqrt(d_k). With d_model=192 and heads=8, which d_k and scale follow?

(a) d_k=24; scale=24.00
(b) d_k=24; scale=sqrt(24)=4.90
(c) d_k=192; scale=sqrt(192)=13.86
(d) d_k=8; scale=sqrt(8)=2.83
### Question 4

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator quantizes a Chapter 8 edge model. Float32 storage is 4 bytes per parameter. INT8 storage is 1 byte per parameter plus 8 bytes of scale metadata per tensor. The model has 78,000 parameters and 12 tensors. Which INT8 size and compression ratio follow?

(a) 78,096 bytes; 4.00x
(b) 78,000 bytes; 4.00x
(c) 312,000 bytes; 1.00x
(d) 78,096 bytes; 0.25x
### Question 5

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator screens local model updates before aggregation. The rule in this question flags an update when gradient_norm > 3.0. The reported norms are 1.3, 1.6, 4.5, 1.0. How many updates are flagged?

(a) 3
(b) No determinate answer can be computed from the stated rule.
(c) 4
(d) 1
### Question 6

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant uses Chapter 8 intervention-effect reasoning. The local rule is causal_effect = P(alert | do(control enabled)) - P(alert | do(control disabled)). P(alert | do(disabled))=0.21; P(alert | do(enabled))=0.13. Which effect follows?

(a) 0.34
(b) No determinate answer can be computed from the stated rule.
(c) -0.08
(d) 0.08
### Question 7

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network applies an update-acceptance gate. The rule is accept only if all four booleans are true: privacy_proof_valid, norm_within_limit, selected_by_robust_aggregator, and epsilon_budget_remaining. Observed values are privacy_proof_valid=True, norm_within_limit=True, selected_by_robust_aggregator=True, epsilon_budget_remaining=True. Which decision follows?

(a) reset the global model
(b) accept update
(c) quarantine update
(d) down-weight but accept update
### Question 8

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program compares local and global F1 for a federated detector. The rule is investigate drift only when local_F1 - global_F1 > 0.10 and holdout_F1 is more than 0.05 below local_F1. local_F1=0.82, global_F1=0.62, holdout_F1=0.68. Which result follows?

(a) drift=0.20; investigate drift
(b) drift=0.20; no drift escalation
(c) drift=-0.20; no drift escalation
(d) No determinate answer can be computed from the stated rule.
### Question 9

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative estimates communication reduction. The self-contained comparison is raw telemetry bytes = samples_per_site * feature_count * 4 * sites, while a model update sends one float32 value per feature per site. There are 7 sites, 520 samples per site, and 47 features. Which reduction ratio follows?

(a) 7.0x
(b) 47.0x
(c) 0.002x
(d) 520.0x
### Question 10

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site aggregates one federated anomaly-model parameter. The FedAvg rule in this question is weighted_parameter = sum(site_samples * site_parameter) / sum(site_samples). Sites report (60, 0.20), (180, 0.35), and (130, 0.10) as (samples, parameter). Which aggregate follows?

(a) 123.333
(b) 0.312
(c) 0.238
(d) 0.217
### Question 11

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program tracks a Chapter 8 privacy budget. The rule is remaining_rounds = floor((epsilon_budget - epsilon_spent) / epsilon_per_round). The budget is 10.0, epsilon_spent is 2.1, and each additional round consumes 1.00. Which count follows?

(a) 6 rounds
(b) 7 rounds
(c) 8 rounds
(d) 10 rounds
### Question 12

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority configures Multi-Krum for a federated IoT detector. The self-contained safety condition is n >= 2f + 3, where n is the number of submitted site updates and f is the maximum Byzantine update count tolerated. Here n=7. What is the largest integer f allowed by the condition?

(a) f = 2
(b) f = 3
(c) No determinate answer can be computed from the stated rule.
(d) f = 1
### Question 13

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility audits a TransformerIDS model. The stem defines d_k = d_model / attention_heads and scaled dot-product attention divides the dot product by sqrt(d_k). With d_model=96 and heads=4, which d_k and scale follow?

(a) d_k=96; scale=sqrt(96)=9.80
(b) d_k=4; scale=sqrt(4)=2.00
(c) d_k=24; scale=24.00
(d) d_k=24; scale=sqrt(24)=4.90
### Question 14

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network quantizes a Chapter 8 edge model. Float32 storage is 4 bytes per parameter. INT8 storage is 1 byte per parameter plus 8 bytes of scale metadata per tensor. The model has 42,000 parameters and 12 tensors. Which INT8 size and compression ratio follow?

(a) 168,000 bytes; 1.00x
(b) 42,096 bytes; 0.25x
(c) 42,096 bytes; 3.99x
(d) 42,000 bytes; 4.00x
### Question 15

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority screens local model updates before aggregation. The rule in this question flags an update when gradient_norm > 3.0. The reported norms are 1.7, 1.2, 4.5, 1.0. How many updates are flagged?

(a) 4
(b) 1
(c) 3
(d) No determinate answer can be computed from the stated rule.
### Question 16

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator uses Chapter 8 intervention-effect reasoning. The local rule is causal_effect = P(alert | do(control enabled)) - P(alert | do(control disabled)). P(alert | do(disabled))=0.21; P(alert | do(enabled))=0.17. Which effect follows?

(a) -0.04
(b) 0.04
(c) 0.38
(d) No determinate answer can be computed from the stated rule.
### Question 17

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator applies an update-acceptance gate. The rule is accept only if all four booleans are true: privacy_proof_valid, norm_within_limit, selected_by_robust_aggregator, and epsilon_budget_remaining. Observed values are privacy_proof_valid=True, norm_within_limit=True, selected_by_robust_aggregator=True, epsilon_budget_remaining=True. Which decision follows?

(a) quarantine update
(b) down-weight but accept update
(c) reset the global model
(d) accept update
### Question 18

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant compares local and global F1 for a federated detector. The rule is investigate drift only when local_F1 - global_F1 > 0.10 and holdout_F1 is more than 0.05 below local_F1. local_F1=0.82, global_F1=0.68, holdout_F1=0.70. Which result follows?

(a) drift=-0.14; no drift escalation
(b) No determinate answer can be computed from the stated rule.
(c) drift=0.14; investigate drift
(d) drift=0.14; no drift escalation
### Question 19

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network estimates communication reduction. The self-contained comparison is raw telemetry bytes = samples_per_site * feature_count * 4 * sites, while a model update sends one float32 value per feature per site. There are 7 sites, 760 samples per site, and 47 features. Which reduction ratio follows?

(a) 0.001x
(b) 760.0x
(c) 7.0x
(d) 47.0x
### Question 20

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program aggregates one federated anomaly-model parameter. The FedAvg rule in this question is weighted_parameter = sum(site_samples * site_parameter) / sum(site_samples). Sites report (60, 0.20), (130, 0.35), and (115, 0.10) as (samples, parameter). Which aggregate follows?

(a) 0.226
(b) 0.217
(c) 101.667
(d) 0.303
### Question 21

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative tracks a Chapter 8 privacy budget. The rule is remaining_rounds = floor((epsilon_budget - epsilon_spent) / epsilon_per_round). The budget is 10.0, epsilon_spent is 2.1, and each additional round consumes 0.50. Which count follows?

(a) 16 rounds
(b) 20 rounds
(c) 14 rounds
(d) 15 rounds
### Question 22

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site configures Multi-Krum for a federated IoT detector. The self-contained safety condition is n >= 2f + 3, where n is the number of submitted site updates and f is the maximum Byzantine update count tolerated. Here n=11. What is the largest integer f allowed by the condition?

(a) No determinate answer can be computed from the stated rule.
(b) f = 3
(c) f = 4
(d) f = 5
### Question 23

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program audits a TransformerIDS model. The stem defines d_k = d_model / attention_heads and scaled dot-product attention divides the dot product by sqrt(d_k). With d_model=192 and heads=8, which d_k and scale follow?

(a) d_k=24; scale=24.00
(b) d_k=24; scale=sqrt(24)=4.90
(c) d_k=192; scale=sqrt(192)=13.86
(d) d_k=8; scale=sqrt(8)=2.83
### Question 24

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority quantizes a Chapter 8 edge model. Float32 storage is 4 bytes per parameter. INT8 storage is 1 byte per parameter plus 8 bytes of scale metadata per tensor. The model has 69,000 parameters and 12 tensors. Which INT8 size and compression ratio follow?

(a) 69,096 bytes; 3.99x
(b) 69,000 bytes; 4.00x
(c) 276,000 bytes; 1.00x
(d) 69,096 bytes; 0.25x
### Question 25

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility screens local model updates before aggregation. The rule in this question flags an update when gradient_norm > 3.0. The reported norms are 1.3, 1.4, 4.5, 1.0. How many updates are flagged?

(a) 3
(b) No determinate answer can be computed from the stated rule.
(c) 4
(d) 1
### Question 26

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network uses Chapter 8 intervention-effect reasoning. The local rule is causal_effect = P(alert | do(control enabled)) - P(alert | do(control disabled)). P(alert | do(disabled))=0.21; P(alert | do(enabled))=0.13. Which effect follows?

(a) 0.34
(b) No determinate answer can be computed from the stated rule.
(c) -0.08
(d) 0.08
### Question 27

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority applies an update-acceptance gate. The rule is accept only if all four booleans are true: privacy_proof_valid, norm_within_limit, selected_by_robust_aggregator, and epsilon_budget_remaining. Observed values are privacy_proof_valid=False, norm_within_limit=True, selected_by_robust_aggregator=True, epsilon_budget_remaining=True. Which decision follows?

(a) reset the global model
(b) quarantine update
(c) accept update
(d) down-weight but accept update
### Question 28

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator compares local and global F1 for a federated detector. The rule is investigate drift only when local_F1 - global_F1 > 0.10 and holdout_F1 is more than 0.05 below local_F1. local_F1=0.82, global_F1=0.62, holdout_F1=0.66. Which result follows?

(a) drift=0.20; investigate drift
(b) drift=0.20; no drift escalation
(c) drift=-0.20; no drift escalation
(d) No determinate answer can be computed from the stated rule.
### Question 29

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator estimates communication reduction. The self-contained comparison is raw telemetry bytes = samples_per_site * feature_count * 4 * sites, while a model update sends one float32 value per feature per site. There are 7 sites, 1000 samples per site, and 47 features. Which reduction ratio follows?

(a) 7.0x
(b) 47.0x
(c) 0.001x
(d) 1000.0x
### Question 30

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant aggregates one federated anomaly-model parameter. The FedAvg rule in this question is weighted_parameter = sum(site_samples * site_parameter) / sum(site_samples). Sites report (60, 0.20), (80, 0.35), and (100, 0.10) as (samples, parameter). Which aggregate follows?

(a) 80.000
(b) 0.286
(c) 0.208
(d) 0.217
### Question 31

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network tracks a Chapter 8 privacy budget. The rule is remaining_rounds = floor((epsilon_budget - epsilon_spent) / epsilon_per_round). The budget is 10.0, epsilon_spent is 2.1, and each additional round consumes 1.00. Which count follows?

(a) 6 rounds
(b) 7 rounds
(c) 8 rounds
(d) 10 rounds
### Question 32

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program configures Multi-Krum for a federated IoT detector. The self-contained safety condition is n >= 2f + 3, where n is the number of submitted site updates and f is the maximum Byzantine update count tolerated. Here n=7. What is the largest integer f allowed by the condition?

(a) f = 2
(b) f = 3
(c) No determinate answer can be computed from the stated rule.
(d) f = 1
### Question 33

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative audits a TransformerIDS model. The stem defines d_k = d_model / attention_heads and scaled dot-product attention divides the dot product by sqrt(d_k). With d_model=96 and heads=4, which d_k and scale follow?

(a) d_k=96; scale=sqrt(96)=9.80
(b) d_k=4; scale=sqrt(4)=2.00
(c) d_k=24; scale=24.00
(d) d_k=24; scale=sqrt(24)=4.90
### Question 34

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site quantizes a Chapter 8 edge model. Float32 storage is 4 bytes per parameter. INT8 storage is 1 byte per parameter plus 8 bytes of scale metadata per tensor. The model has 96,000 parameters and 12 tensors. Which INT8 size and compression ratio follow?

(a) 384,000 bytes; 1.00x
(b) 96,096 bytes; 0.25x
(c) 96,096 bytes; 4.00x
(d) 96,000 bytes; 4.00x
### Question 35

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program screens local model updates before aggregation. The rule in this question flags an update when gradient_norm > 3.0. The reported norms are 1.7, 1.6, 4.5, 1.0. How many updates are flagged?

(a) 4
(b) 1
(c) 3
(d) No determinate answer can be computed from the stated rule.
### Question 36

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority uses Chapter 8 intervention-effect reasoning. The local rule is causal_effect = P(alert | do(control enabled)) - P(alert | do(control disabled)). P(alert | do(disabled))=0.21; P(alert | do(enabled))=0.17. Which effect follows?

(a) -0.04
(b) 0.04
(c) 0.38
(d) No determinate answer can be computed from the stated rule.
### Question 37

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility applies an update-acceptance gate. The rule is accept only if all four booleans are true: privacy_proof_valid, norm_within_limit, selected_by_robust_aggregator, and epsilon_budget_remaining. Observed values are privacy_proof_valid=True, norm_within_limit=True, selected_by_robust_aggregator=True, epsilon_budget_remaining=True. Which decision follows?

(a) quarantine update
(b) down-weight but accept update
(c) reset the global model
(d) accept update
### Question 38

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network compares local and global F1 for a federated detector. The rule is investigate drift only when local_F1 - global_F1 > 0.10 and holdout_F1 is more than 0.05 below local_F1. local_F1=0.82, global_F1=0.68, holdout_F1=0.68. Which result follows?

(a) drift=-0.14; no drift escalation
(b) No determinate answer can be computed from the stated rule.
(c) drift=0.14; investigate drift
(d) drift=0.14; no drift escalation
### Question 39

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority estimates communication reduction. The self-contained comparison is raw telemetry bytes = samples_per_site * feature_count * 4 * sites, while a model update sends one float32 value per feature per site. There are 7 sites, 1240 samples per site, and 47 features. Which reduction ratio follows?

(a) 0.001x
(b) 1240.0x
(c) 7.0x
(d) 47.0x
### Question 40

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator aggregates one federated anomaly-model parameter. The FedAvg rule in this question is weighted_parameter = sum(site_samples * site_parameter) / sum(site_samples). Sites report (60, 0.20), (180, 0.35), and (85, 0.10) as (samples, parameter). Which aggregate follows?

(a) 0.257
(b) 0.217
(c) 108.333
(d) 0.312
### Question 41

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator tracks a Chapter 8 privacy budget. The rule is remaining_rounds = floor((epsilon_budget - epsilon_spent) / epsilon_per_round). The budget is 10.0, epsilon_spent is 2.1, and each additional round consumes 0.50. Which count follows?

(a) 16 rounds
(b) 20 rounds
(c) 14 rounds
(d) 15 rounds
### Question 42

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant configures Multi-Krum for a federated IoT detector. The self-contained safety condition is n >= 2f + 3, where n is the number of submitted site updates and f is the maximum Byzantine update count tolerated. Here n=11. What is the largest integer f allowed by the condition?

(a) No determinate answer can be computed from the stated rule.
(b) f = 3
(c) f = 4
(d) f = 5
### Question 43

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network audits a TransformerIDS model. The stem defines d_k = d_model / attention_heads and scaled dot-product attention divides the dot product by sqrt(d_k). With d_model=192 and heads=8, which d_k and scale follow?

(a) d_k=24; scale=24.00
(b) d_k=24; scale=sqrt(24)=4.90
(c) d_k=192; scale=sqrt(192)=13.86
(d) d_k=8; scale=sqrt(8)=2.83
### Question 44

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program quantizes a Chapter 8 edge model. Float32 storage is 4 bytes per parameter. INT8 storage is 1 byte per parameter plus 8 bytes of scale metadata per tensor. The model has 60,000 parameters and 12 tensors. Which INT8 size and compression ratio follow?

(a) 60,096 bytes; 3.99x
(b) 60,000 bytes; 4.00x
(c) 240,000 bytes; 1.00x
(d) 60,096 bytes; 0.25x
### Question 45

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative screens local model updates before aggregation. The rule in this question flags an update when gradient_norm > 3.0. The reported norms are 1.3, 1.2, 4.5, 1.0. How many updates are flagged?

(a) 3
(b) No determinate answer can be computed from the stated rule.
(c) 4
(d) 1
### Question 46

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site uses Chapter 8 intervention-effect reasoning. The local rule is causal_effect = P(alert | do(control enabled)) - P(alert | do(control disabled)). P(alert | do(disabled))=0.21; P(alert | do(enabled))=0.13. Which effect follows?

(a) 0.34
(b) No determinate answer can be computed from the stated rule.
(c) -0.08
(d) 0.08
### Question 47

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program applies an update-acceptance gate. The rule is accept only if all four booleans are true: privacy_proof_valid, norm_within_limit, selected_by_robust_aggregator, and epsilon_budget_remaining. Observed values are privacy_proof_valid=True, norm_within_limit=True, selected_by_robust_aggregator=True, epsilon_budget_remaining=True. Which decision follows?

(a) reset the global model
(b) accept update
(c) quarantine update
(d) down-weight but accept update
### Question 48

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority compares local and global F1 for a federated detector. The rule is investigate drift only when local_F1 - global_F1 > 0.10 and holdout_F1 is more than 0.05 below local_F1. local_F1=0.82, global_F1=0.62, holdout_F1=0.70. Which result follows?

(a) drift=0.20; investigate drift
(b) drift=0.20; no drift escalation
(c) drift=-0.20; no drift escalation
(d) No determinate answer can be computed from the stated rule.
### Question 49

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility estimates communication reduction. The self-contained comparison is raw telemetry bytes = samples_per_site * feature_count * 4 * sites, while a model update sends one float32 value per feature per site. There are 7 sites, 520 samples per site, and 47 features. Which reduction ratio follows?

(a) 7.0x
(b) 47.0x
(c) 0.002x
(d) 520.0x
### Question 50

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network aggregates one federated anomaly-model parameter. The FedAvg rule in this question is weighted_parameter = sum(site_samples * site_parameter) / sum(site_samples). Sites report (60, 0.20), (130, 0.35), and (70, 0.10) as (samples, parameter). Which aggregate follows?

(a) 86.667
(b) 0.303
(c) 0.248
(d) 0.217
