Consider additional requirements and technology to further complicate your analysis of an Automated Teller Machine (ATM) design:

Use eye-tracker data to further analyze the product

Eye-tracker data could show us where users look first when they use the interface which would allow us to better place the key features they are looking for in the places they look first

Consider accessibility (universal usability) issues such as lighting, physical placement of ATM, etc.

The ATM should be placed on ground level (not raised or lowered) so that users do not have to crane their posture up or down to interact with it. Also it should be in a well-lit environment so that users can correctly see the interface they are using. Furthermore the ATM should be placed in its own space, away from other things people want to use so that users are not crammed into a space and so that, if a queue of users forms to use it, they do not block the paths of others.

Consider user profile issues, e.g. is this the first time a user is using an ATM?

Perhaps to help new users, if more than a couple of user errors occur, the interface should begin to display non-intrusive help messages to guide them towards their goal.

Requirement to perform beta and/or market tests?

Positioning and lighting of the environment of the ATM could be tested in control groups to find the most preferred setup of the ATM by users.

Are there other stress factors such as a looming time deadline or a personal safety issue?

One stress factor users might encounter is if they are using the ATM while a large queue has formed behind them or if they have waited a long time to use the ATM. The frustration of waiting a long time and the stress of wanting to use the ATM quickly so others can use the machine will cause the users to make more mistakes and have less pleasant experiences.

Review the iOS Human Interface Guidelines in the iOS Developer Library at: https://developer.apple.com/ios/human-interface-guidelines/

1) select one guideline that makes perfect sense and seems easy to incorporate into a design

In my opinion, clarity is the most logical of the guidelines. It is straight-forward to have a guideline which asks the developer to make things easier to read, see, and interact with.

2) select another guideline that is much less clear requiring further explanation or analysis to incorporate into a design.

The deference guideline sounds much more abstract and harder to implement. For example, it asks the developer to make subjective improvements to the interface such as being "beautiful" and "easy to understand."

At present, the drive to use Big Data to define or enhance corporate strategies seems to be a global business trend. State an example of where this data can improve a business, focusing on user interface aspects.

One could examine big data such as user click positions, eye-tracking data, and so on from mass repositories and try to find trending key points where people look and click in order to find better places to position elements.

Cite a past experience where user interface development methods might apply to another system development activity that might not have a strong user interface component.