Human Factors Midterm
What is the z-score for a 5th percentile measurement (normally distributed)?
(-1.65)
In general, the computer monitor for an office worker should be located so the center of the screen is
10 -15 degrees below the worker's horizontal line of sight
An auditory signal (e.g., alarm) that must be heard above the background noise that may be masking the signal should be at least ______ dB above the background noise intensity
15
Consider the design for an adjustable height work area at which a small 6" x 6" x 6" packing box is folded, taped and labeled prior to filling. If the workers are standing, how high should the worksurface be located?
2-4 inches below the worker's standing elbow height
A worker who performs a manual material handling task that results in a compression force at her L5/S1 joint just exceeding the NIOSH disc compression limit is how many times more likely to injure her low back than a worker whose work does not exceed this limit (e.g., a worker performing a seated assembly task)?
3x higher LBI risk
The autofill option in the previous question operates at which level of automation?
4 - Carry out option with approval
A worker is exposed to 80 dB for 2 hours, 85 dB for 5 hours, and 95 dB for 1 hour. What is the noise dose?
62.5
By age 60, approximately how many workers out of every 10 will have experienced a significant low back injury?
7
A sound level meter is placed 10 feet away from a machine and records an average SPL of 84 dB. If the measurement can be assumed to be a free-field measurement and the meter is place 40 feet away, what does the meter read?
72
When designing the width of a seat, which of the following would be the preferred stature on which to base the dimensions?
95th percentile female
A person's strength is poorly predicted by their: Gender Age Physical size Weight All of the items listed
All of the items listed
Improving how task information is "chunked" can reduce mental workload. To improve "chunking", a person can do which of the following? All of the items listed None of the items listed Use spaces or hyphens to separate long number strings into small groups (e.g., phone numbers) Use common strings of 3 or 4 letters (e.g., CNN) Use common sequences of numbers (e.g., "747")
All of the items listed
When designing a label, which of the following is considered a key design criterion? None of the items listed Location Meaningfulness All of the items listed Visibility and legibility Discriminability
All of the items listed
With respect to reading blue ink written on gray paper and holding all other characteristics constant, which of the following will improve the ability of a person to detect a critical detail? All of the items listed White paper None of the items listed Black ink Higher lumen light source
All of the items listed
The classic "drag & drop" method of file deletion on a Windows or Macintosh desktop (graphical user interface) best adheres to which interaction design principle? None of the principles listed Simplify and structure task sequences Make system structure and affordances visible All of the principles listed Match system to the real world Support recognition rather than forcing recall
All of the principles listed
What type of anthropometric data for a body segment is often used to provide data for a biomechanical analysis? Link length All of the types of data listed None of the types of data listed Center of mass location Mass (weight)
All of the types of data listed
The use of the different "eye-cons" in the Baxter robot's interface best follows which automation principle listed below? Signal inability to satisfy role Keep the person informed All principles listed Make trustable and polite
All principles listed
In various Internet browsers, an autofill feature can be enabled that "remembers" what websites with which you have accounts and will fill in your stored login details (username/email and password) associated with the site when you go to the login page. This best exemplifies which interaction design principle?
Anticipate needs
In the "factory of the mind" concept, which of the following is a resource that can be applied to any of the information processing stages from sensory processing to response execution?
Attention
In the factory of the mind concept, which of the following is a resource that can be applied to any of the information processing stages from sensory processing to response execution?
Attention
What factor improves one's ability to multi-task?
Automaticity of one or more tasks
A physician diagnosed correctly a patient, Sam, with disease X. The physician next saw another patient, Priya, with similar symptoms and correctly diagnosed her with disease X. Next, the doctor sees Ping, who presents with many of the same symptoms, and diagnoses her with disease X. This turned out to be the wrong diagnosis. Which best explains why the doctor got Ping's diagnosis wrong?
Availability
When designing a self-serve checkout counter for a local grocery store, what anthropometric design approach should you apply for specifying the vertical distance between the floor and the scanner surface?
Average
Which guideline for lifting is intended primarily to help workers avoid high force spikes that can lead to a person developing microfractures in their vertebrae?
Avoid fast, jerky lifts
The usability of a product or process depends on understanding how a person behaves in response to the other elements within the overall system context. This requires knowledge of the typical user's
Both items
According to Baddeley, what is the name of the component in working memory that allocates attention and coordinates information flow between three different "storage" buffers?
Central executive
A year ago, I bought 100 shares of stock in XTC Computer at $30/share. The stock is currently trading at $25/share. My investment advisor at TIAA-CREF has told me that the stock has a 75% chance of falling to $20/share in a month, but a 25% chance of rising to $35/share. Due to unexpected expenses, I need to sell the stock. I can either sell the stock now or wait a month to sell. Of the three categories of decision making described in class, what kind of decision-making task am I performing? Choice Prediction Diagnosis
Choice
What term best describes automation that makes it easier to complete easy tasks but harder to complete difficult tasks?
Clumsy automation
In September 2020, an incident happened in Canada involving a Tesla Model SLinks to an external site. that was speeding 140 km/h (87 mph) in a 100 km/h zone. According to one report, the Alberta Royal Canadian Mounted Police (RCMP) was alerted of the incident by a truck driver who noticed that both front seats were completely reclined, and both occupants appeared to be sleeping. The vehicle was set to the Tesla's self-driving Autopilot mode and, when the RCMP began pursuing the vehicle, the RCMP reported that it automatically actually sped up to 150 km/h (93 mph) - apparently matching the RCMP patrol car's speed - before the driver awakened and stopped the car. With respect to the driver, what is the MOST LIKELY problem or issue in terms of automation that was occurring in this situation?
Complacency
The "sluggish beta" phenomenon in signal detection theory is an example of what kind of decision making bias discussed in this section?
Conservative
In terms of assessing mental workload, which of the following is NOT an issue with using physiological measures? Data collection can interfere with task performance Measurements are not well-correlated with workload Equipment and sensors can be expensive All of these are issues
Data collection can interfere with task performance
Consider the scenario in which a driver attempts to call someone on a cellular phone while navigating through heavy traffic. In the process, he misses the exit he was looking for. This represents a failure of what type of attention?
Divided
Which tasks are most likely to be multi-tasked successfully?
Driving a car and listening to a podcast
What usability measure for an interface does the Keystroke Level Model assess?
Efficiency
As defined in this class, there are five elements that influence the performance of a system. Based on how I presented this in class (i.e., the mnemonic), what is the fourth (4th) element?
Environment
When covering "oops" in class, I talked about products that were designed in ways that appear similar to earlier designs but operated differently (e.g., the minivan seat, the water spigot). Which of the following best explains why these types of designs lead to errors?
Expectations/prior experience
Which of Newton's laws underlies the principle of "avoiding fast, jerky lifts"?
F = ma
A permanent threshold shift (PTS) in hearing resulting from exposure to occupational noise is most pronounced around 1000 Hz in our range of hearing.
False
A person holding a 20 lb. object directly above their shoulder with their arm held straight (vertically) is creating a large moment about the elbow and shoulder.
False
A person with 20/40 vision has better visual acuity than a person with 20/10 vision
False
According to the proximity compatibility principle, controls should be located close to each other and aesthetically arranged whenever it is possible to do so
False
As a person's perception of workload increases, their task performance will decline (longer times, more errors, etc.).
False
Direct glare occurs when the light reflected from a surface interferes with a task
False
For a given lifting task, a small female has a higher risk of suffering a low back injury than a large male
False
From a functional allocation standpoint, automation designers generally should leave the details to the person and the "big picture" (e.g., context) to the machine/software.
False
Most anthropometric design tables provide mainly functional data since that type of data most accurately represents work activities.
False
Situational awareness refers to one's ability to recall a past situation similar to the present situation in order to respond appropriately and avoid errors.
False
Using the optimal response criterion yields perfect detection performance
False
With respect to the system context when designing a product or process, there is no interaction between how the design might cause users to make an error, get hurt, or get frustrated (for example, an error will have no bearing on whether someone gets hurt or frustrated - these three issues are independent of each other).
False
Which of the following principles or laws tells us that it is unreasonable to expect both perfect performance and high production rates from workers performing difficult assembly tasks in a manufacturing setting?
Fitt's Law
The specific location in the eye in which cones are most concentrated is called the
Fovea
Which principle of work area component arrangement should be applied if the goal is to minimize production time from cycle to cycle in a manual assembly task?
Frequency of use
As presented in this class, incorporating user-centered design methods to keep someone from going "AARGH" is helping them avoid
Frustration
A research assistant has been assigned to search, select and extract data from dozens of spreadsheets of raw data containing 16 columns and up to 25000 rows of data. In particular, she is locating at two different columns of data and, in each, trying to identify rows where the data stream transitions from 1 to 0 and from 0 to 1. At each transition, the data from selected columns in the row must be copied into another worksheet in the spreadsheet. Which of the following input modalities would be best suited for helping with this task?
Function keys/keyboard shortcuts
We use our network of touch and position sensors to perceive ("feel") our place in the environment (world) around us. Which term pertains to the use of these sensors to detect the size and shape of an object as well as the force required to handle it?
Haptic
Designing products, systems and processes to avoid injuries requires knowledge about a lot of different things, but the most crucial element to understand is
Human physiology
A worker is setting anchors for a horizontal lifeline to which roofers will attach their fall protection lanyards. She is using her training and past experience in similar work environments and buildings to evaluate which locations, if any, would be most suitable for the anchors to withstand the forces exerted on them should a worker fall. How is this training and past experience most likely organized in her long term memory?
In a mental model
One guideline for reducing the risk of low back injury in lifting tasks is to "avoid twisting while lifting." What is the most likely consequence if the guideline is ignored?
Increased risk of a herniated (ruptured) intervertebral disc
The intensity of light at the source is measured in units of
Lumens
An increasingly common automated feature in some current vehicles is a lane-keeping feature that will steer the vehicle back into the lane if it senses that the vehicle is crossing the lane boundaries (lines on either side). This, however, is not intended to be a self-steering feature. To counter this, certain vehicles also monitor the driver's steering wheel input when lane-keeping is enabled and, should the driver not make any corrective movements in a preset period of time (e.g., 30 seconds), visual and auditory alerts are triggered to notify the driver to put their hands back on the steering wheel. This, in turn, has its own issues. Most drivers on long, straight stretches of highway will keep their hand(s) on the steering wheel but may not need to make any corrective movements, in which case the alert can become an annoying and repetitive "false alarm." Unfortunately, this alerting feature cannot be disabled or modified without also turning off the automated lane-keeping. What principle of automation is this automated alerting feature MOST LIKELY violating?
Make automation directable
Regarding sound measurement, which of the following statements is true? The pitch of a sound is determined jointly by its frequency and intensity Loudness and sound pressure level are both objective measures of sound intensity Both of the items listed None of the items listed
None of the items listed
This is an example of a proposed digital display for a car. Which principle of display design does the speed indicator satisfy (consider the center section only - not the map or fuel information)? Redundancy gain Proximity compatibility Support visual momentum None of the principles listed Pictorial realism
None of the principles listed
The following is an example of a Gestalt principle that aids conspicuity. Which Gestalt principle is this? ////////|///////
Orientation
The type of search where all items are examined at once and the target object is found because of its conspicuity is called
Parallel search
Constructing a shielded enclosure around a noisy machine to reduce a worker's noise exposure is an example of what type of noise control?
Path
What type of memory describes the act of remembering to do something at a later date (e.g., remembering to take out the garbage in the morning because it's trash day tomorrow)?
Prospective
Which of the following describes episodic memory?
Recall may change over time due to other events
A stop sign best applies which principle of display design?
Redundancy gain
The use of computational algorithms to help people make decisions has skyrocketed in the past 20 years. For example, credit checks are used by many lenders to help them assess the risk that a person may default on their loan and influence the lender's decisions as to eligibility, loan limits and interest rates for an applicant. To do so, these systems pull the applicant's financial data and other information from various sources (e.g., banks, credit card companies, insurance) and use proprietary methods to generate a risk rating for the lender (i.e., a credit score). However, consumer protection groups have noted that many lenders have shifted towards making loan decisions primarily (or solely) on these credit scores. With identity theft, data breaches (i.e., hacks), and reporting errors becoming more common, these groups argue that the databases used by these scoring systems have been compromised and are leading to erroneous judgments about the creditworthiness of applicants, particularly for certain segments of the population. From the lender's perspective, what issue in automation is MOST LIKELY affecting their decisions about whether or not to approve a loan for an individual?
Reliability
Now assume our driver from earlier is trying to retrieve a text message from his phone while driving on the highway. The driver keeps pressing the wrong keys, so he looks away from the road so that he can look at the phone to get the keypresses right. Within 3 seconds of looking away, the car ahead of him slows suddenly and our driver collides ("rear-ends" ) with the slowed vehicle ahead of him. Which type of attention failure was the primary cause of this accident?
Selective
A year ago, I bought 100 shares of stock in XTC Computer at $30/share. The stock is currently trading at $25/share. My investment advisor at TIAA-CREF has told me that the stock has a 75% chance of falling to $20/share in a month, but a 25% chance of rising to $35/share. Due to unexpected expenses, I need to sell the stock. I can either sell the stock now or wait a month to sell. Based on the risk involved, what am I most likely to do?
Sell the stock in a month
A year ago, I bought 100 shares of stock in XTC Computer at $30/share. The stock is currently trading at $25/share. My investment advisor at TIAA-CREF has told me that the stock has a 75% chance of falling to $20/share in a month, but a 25% chance of rising to $35/share. Due to unexpected expenses, I need to sell the stock. I can either sell the stock now or wait a month to sell. According to the expected utility (optimal) model, what should I do?
Sell the stock today
Which sensor in the body is critical to detecting the orientation of our body in space (relative to gravity)?
Semicircular canals
Two factors influence a person's ability to accurately detect whether a stimulus contains a signal or is simply the background noise (no signal). What are they?
Signal to noise ratio and perceptual abilities
The heads-up display used for the SpaceX/ISS docking interface operates at which stage of automation?
Stage 2: Information integration
What type of workload measurement is the NASA-TLX tool?
Subjective
Because of the sheer number of cells that must be searched, our research assistant from the previous question is having trouble verifying if she has correctly identified and copied the data for all of the transitions occurring in each worksheet. According to Norman, what is she having trouble "bridging"?
The gulf of evaluation
A time study reveals that the average completion times for the following tasks, which cannot be done concurrently: Task A = 40 minutes Task B = 15 minutes Task C = 55 minutes A worker has been assigned these three tasks and has 2 hours in which to complete them. Which of the following outcomes is most likely?
The worker will complete the tasks satisfactorily but will experience elevated stress
On an ROC curve, if a person's performance on an SDT scenario falls on the 45-degree diagonal line, what does that indicate about their performance with respect to if they've detected a signal or not?
They're guessing - they have no idea if they detected something or not
With respect to monitoring or inspection tasks that require vigilance, which of the following can help a person maintain high performance levels?
Train people to adopt the optimal beta
The use of the different "eye-cons" in the Baxter robot's interface best follows which automation principle listed below?
Transparency
Digital human models (i.e., avatars) can be used with virtual workspace layouts at the design phase to assess potential ergonomic hazards before the workspace is actually built.
True
One function of the hammer, anvil, and stirrup in the middle ear is to mechanically transmit sound from the tympanic membrane (eardrum) to the oval window
True
One should design an information display for monochrome usage before considering how to incorporate color into the display
True
The basic concept in workplace biomechanics is that the torques required to apply force on an object (e.g., lift or push) should not exceed the worker's ability to generate torque at any of the joints involved.
True
Which direction of travel (by plane) causes the most disruption to a person's circadian rhythm?
West to east
Adjusting which of the following is *most* appropriate for a worker placing filled boxes on a shipping conveyor?
Worker position (relative to workplace)
Under a highly stressful situation, a person may experience difficulty (i.e., degraded performance) with which of the following cognitive functions?
Working memory
A frequency analysis of a sound sample from an office workspace reveals two peaks: a 50 dB peak in the 125 Hz octave bandwidth and a 35 dB peak in the 2000 Hz octave bandwidth. Does the environmental noise exceed the minimum acoustical requirement of "conversation" for the workspace?
Yes
Which of the following is a critical aspect of feedback with respect to a system's response (e.g, display change) to a control action? accuracy all of the items listed immediate (minimal time lag) none of the items listed salience detectable
all of the items listed
Due to the separated location of each eye, each eye sees a object from a slightly different viewpoint. The amount of difference between the images seen by each eye depends on the object's distance from the eye. Which depth perception cue does this describe?
binocular disparity
What would be the most likely anthropometric measurement device used to collect data on hip breadth?
caliper
The gain in the steering system of a vehicle typically depends on the purpose of the vehicle. For example, the steering system in a heavy construction vehicle typically will have ______________ gain while the steering in a racing car will have _____________ gain.
low, high
One can think of a technical report as a type of static display providing information to the reader. As such, many of the design principles for displays can be applied to reports as well. For example, report writers often place important diagrams, data tables and other critical information in an appendix of the reports and instead reference these in the body of the report. This forces the readers to stop reading the body of the report and search through an appendix to find this information. Which display design principle does this violate?
minimizing information access cost
Displaying temperature or altitude information using a moving-pointer/fixed-scale display in a horizontal orientation (as shown) violates the principle of:
pictorial realism
According to signal detection theory, a person who is very willing to respond "yes, it's a signal" when he/she perceives a possible signal is said to be utilizing a ______________ strategy.
risky
To look from one fixed area/object to another fixed area/object, ___ eye movements are used while __ eye movements are used to follow moving targets
saccades, pursuit
Without rehearsal, information processed by a person (e.g., material presented in lecture or the name and/or phone number of a stranger) typically starts to decay (i.e., information fails to be encoded)
shortly after presentation
On the other hand, displaying temperature or altitude information using a moving-scale/fixed-pointer display in a vertical orientation (as shown) violates the principle of
the moving part
Engineers should utilize user-centered design primarily because
they have an ethical obligation to do so
