Research Methods & Evidence-Based Practice Flashcards

An evidence-based wireless design requires a minimum SNR of 25 dB for reliable 802.11ac (Wi-Fi 5) MCS 8 operation. The measured noise floor is -95 dBm. What minimum RSSI must be maintained?

Answer: -70 dBm

SNR = RSSI − Noise Floor; to achieve 25 dB SNR with a -95 dBm noise floor, RSSI must be at least -95 + 25 = -70 dBm.

Which type of survey data is MOST valuable when a healthcare facility needs to prove HIPAA-compliant wireless coverage in all patient areas before a compliance audit?

Answer: Passive survey heatmaps combined with active throughput logs at each care zone

Regulators expect empirical evidence; passive heatmaps prove coverage while active throughput logs prove functional connectivity in every patient area.

During a wireless assessment, an engineer observes high retry rates (>15%) on a 5 GHz AP despite strong RSSI values. Which diagnostic step BEST confirms or rules out a hidden node problem?

Answer: Capture 802.11 frames and look for overlapping transmissions from clients the AP cannot hear

Capturing frames and identifying transmissions that collide without the AP detecting them provides direct evidence of a hidden node condition.

A warehouse deployment uses 900 MHz wireless technology. A researcher comparing it to a 2.4 GHz solution should account for which key propagation difference?

Answer: 900 MHz signals penetrate obstacles and diffract around obstructions more effectively than 2.4 GHz

Lower frequencies experience less free-space path loss and diffract better around obstacles, giving 900 MHz a range and penetration advantage over 2.4 GHz.

When reviewing a vendor's claimed throughput figures for a Wi-Fi 6 AP, which factor MOST commonly accounts for the gap between PHY-layer (theoretical) data rates and actual application throughput?

Answer: MAC layer overhead, CSMA/CA backoff, retransmissions, and TCP/IP protocol overhead

MAC overhead, contention-based access, retransmissions, and upper-layer protocol overhead collectively reduce actual throughput well below the theoretical PHY rate.

An engineer is designing a survey methodology for an outdoor campus network. Which environmental factor MOST requires time-of-day survey repetition to produce reliable evidence?

Answer: Foliage density changes due to wind and seasonal variation affecting signal attenuation

Foliage attenuation varies with wind movement and seasonally with leaf density, so outdoor surveys at different times produce more representative propagation data.

A CWS practitioner must choose between manual walkthrough surveys and robotic/automated survey tools for a 500,000 sq ft distribution center. Which factor MOST favors the automated approach?

Answer: Automated tools provide consistent, repeatable sampling intervals and travel paths, reducing human variability

Automated survey platforms follow precise, repeatable paths and sampling intervals, minimizing surveyor-introduced variability across large-scale environments.