Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
A data scientist is preparing a dataset to train a model that predicts customer churn. The dataset includes a column 'CustomerID' which is a unique identifier for each customer. Should the data scientist include the 'CustomerID' column as a feature in the training data?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Yes, because it uniquely identifies each customer and helps the model differentiate them.
Including a unique identifier is not useful for prediction because the model cannot learn a meaningful relationship between a random ID and the target variable.
B
Best answer
No, because the CustomerID is a random unique identifier with no predictive power for churn.
Correct. Unique identifiers are arbitrary and do not correlate with the outcome. They should be removed to avoid overfitting.
C
Distractor review
Yes, because the model can learn patterns from the numeric values.
While CustomerID might be numeric, it is assigned arbitrarily and does not contain useful patterns for prediction.
D
Distractor review
No, because the CustomerID column contains too many missing values.
The reason is not about missing values; it's that the ID has no predictive correlation. Missingness is a separate data quality issue.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Related practice questions
Related AI-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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FAQ
Questions learners often ask
What does this AI-900 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: No, because the CustomerID is a random unique identifier with no predictive power for churn. — Unique identifiers like CustomerID do not have any correlation with the target variable (churn). Including them can lead to overfitting on noise and does not help the model generalize to new customers. Therefore, they should be excluded from the feature set.
What should I do if I get this AI-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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