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CBSE Class 10 · Artificial Intelligence, code 417 · Unit 3, Evaluating Models, 2026-27
These evaluating models class 10 questions and answers cover Unit 3 of CBSE AI 417 for the 2026-27 session: why a model must be tested, how the train-test split works, what accuracy and error mean on a real table, when precision beats recall, and the ethical side of judging a model. The ideas come first, then written answers sized for one, two and four marks. Confusion matrix calculations have a page of their own, linked below.
Live online · Unit 3 explained and answered · written answers marked against the scheme · case studies timed · first class free
Start here
The 417 course whose Class 10 batch teaches Evaluating Models, the AI and ML course for students who want to see real models scored, and the data science course where splits and metrics are run in Python.

The batch / 417 Class 10
The full 417 course: Unit 3 taught as ideas first, then written answers and case studies marked in class against the value points.
Open the course →
Go further / AI and ML
Train a small model, hold back a test set and watch its score change, so the reasons behind evaluation are seen, not memorised.
Open the course →
Hands-on / Data science
Python notebooks where the train-test split, accuracy and error are computed on real data, a step beyond the board unit.
Open the course →Ans. The short version
Evaluating Models is Unit 3 of CBSE Class 10 AI (417), worth 10 of the 50 theory marks in 2026-27. It asks why a model is tested on data it has never seen (the train-test split), how accuracy and error are worked out, how a confusion matrix gives accuracy, precision, recall and F1 score, which metric matters when false positives or false negatives cost more, and the ethical concerns of bias, transparency and accountability. Modern Age Coders teaches the unit live in a Monday and Wednesday 9:00 PM IST batch, with written answers marked in class, or personalised one to one.
Q1. Why evaluate at all?
We evaluate a model to find out how well it will predict on new data it has never seen, before anyone relies on it. A model that looks perfect on the data it learnt from can still fail badly in the real world.
Evaluation is the last stage of the AI project cycle, after problem scoping, data acquisition, data exploration and modelling. Its result often sends the team back a step: a weak score can mean more data, cleaner data or a different model. In an answer, saying that evaluation can loop the project back earns credit that a bare definition misses.
The cycle itself, with its ethical frameworks, is covered on the project cycle and ethics page.
| Unit 3 topic | What you must be able to do | Shape it usually takes |
|---|---|---|
| Importance of evaluation | Give reasons, link to overfitting | Objective item or two-mark answer |
| Train-test split | Define it, say why the test set stays unseen | Two-mark answer |
| Accuracy and error | Find error, error rate and accuracy from actual and predicted values | Short calculation |
| Classification metrics | Build a confusion matrix, find accuracy, precision, recall, F1 | Objective items and a case-based numerical |
| Precision or recall | Pick the metric for a scenario and justify it | Two or four marks |
| Ethical concerns | Explain bias, transparency and accountability with an example | Two-mark answer |
Q2. What is the train-test split?
The train-test split divides a labelled dataset into two parts: a training set the model learns from, and a testing set kept aside to check the model afterwards. Because the test set is unseen, its score is a fair guess of real-world performance.
data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] cut = int(len(data) * 0.8) train, test = data[:cut], data[cut:] print(len(train), len(test)) print(train, test) # Output: # 8 2 # [1, 2, 3, 4, 5, 6, 7, 8] [9, 10]
Not something the theory paper asks you to write. It only shows the split: eight items to learn from, two held back. Real projects shuffle the rows first so both parts look alike.
| Training set | Testing set | |
|---|---|---|
| Purpose | The model finds patterns in it | Checks the finished model |
| Seen by the model while learning? | Yes | No, never |
| Usual share | The larger part | The smaller part |
| 1,200 photos at 80:20 | 960 | 240 |
| 1,200 photos at 70:30 | 840 | 360 |
The model has already seen those answers. A high score there can come from memory, not understanding, which is exactly what overfitting means.
The handbook explains the split without fixing a ratio. 80:20 and 70:30 are common in practice; name one as an example, not as a rule.
When the dataset is large enough that both parts still represent every kind of example. A tiny dataset split in two leaves each part too thin to trust.
Q3. Accuracy and error
Error is the gap between what the model predicted and what actually happened. For a number prediction, error = |actual minus predicted|, error rate = error divided by actual, and accuracy = 1 minus error rate.
A model predicts how long five long
bus journeys take, in minutes. Find
the error, error rate and accuracy of
each, then the overall accuracy.
error = |actual - predicted|
error rate = error / actual
accuracy = 1 - error rate
overall = (0.96 + 0.90 + 0.95
+ 1.00 + 0.95) / 5
= 4.76 / 5 = 0.952, about 95%
Take the absolute value: a prediction 18 too high and one 18 too low are equally wrong. Divide by the actual value, never the predicted one.
| Journey | Actual | Predicted | Error | Error rate | Accuracy |
|---|---|---|---|---|---|
| 1 | 250 | 240 | 10 | 0.04 | 0.96 |
| 2 | 180 | 198 | 18 | 0.10 | 0.90 |
| 3 | 320 | 304 | 16 | 0.05 | 0.95 |
| 4 | 150 | 150 | 0 | 0.00 | 1.00 |
| 5 | 400 | 380 | 20 | 0.05 | 0.95 |
| Overall accuracy (mean) | 0.952 | ||||
When the model sorts things into classes, accuracy is simply the share of correct predictions. If a leaf-disease model labels 50 test photos and gets 46 right, its accuracy is 46 / 50 = 0.92 and its error rate is 4 / 50 = 0.08. The two always add up to 1.
Splitting those 50 predictions into true and false positives and negatives is the confusion matrix, and that is where most Unit 3 calculation marks sit. Twelve graded problems with full working are on confusion matrix class 10 AI numericals, and every formula on one page is on the 417 formula sheet.
Q4. Precision or recall?
Choose precision when a false alarm (false positive) is the costly mistake, and recall when a miss (false negative) is the costly mistake. When both matter and one class is rare, report the F1 score, which balances the two.
Precision asks: of everything the model flagged, how much was right? Recall asks: of everything that was really there, how much did the model catch?
| Scenario | Costlier error | Metric |
|---|---|---|
| Screening for a serious illness | Missing a patient | Recall |
| Moving emails to the spam folder | Hiding a real email | Precision |
| Flagging card fraud | Letting a fraud through | Recall |
| Approving a rocket launch on a forecast of good weather | Launching in bad weather | Precision |
| Spotting forest fires from satellite images | An unseen fire | Recall |
| Recommending a video to a child | An unsuitable video shown | Precision |
| Rare defects, both errors costly | Neither clearly | F1 score |
A four-mark answer names the positive class, says which wrong prediction hurts more and why, then names the metric. Writing only "recall" scores one mark at most. Is accuracy alone enough? No: on a dataset where 99 of 100 cases are negative, a model that always says no is 99% accurate and useless. Worked numbers for that trap sit on the numericals page, and objective practice on the same ideas is in the class 10 AI MCQ bank.
Q5. The ethics of evaluation
The ethical concerns are bias, transparency and accountability: the test must be fair to every group, the way a model was scored must be explained openly, and the people who chose the metric must answer for its effects. An honest accuracy figure is part of being transparent.
If the test set holds mostly one kind of person, a high score says little about everyone else. A face-unlock model tested only on adults may fail for children and nobody notices. Fair evaluation tests every group the model will meet.
Users should know which data the model was tested on, which metric was used and what the score leaves out. Quoting 98% accuracy on a lopsided dataset while hiding a poor recall is misleading, even when the number is true.
Someone must take responsibility for the metric chosen and its consequences. If a loan model is tuned for precision and that turns away honest applicants, the team that chose it owns that result.
A school reports that its attendance face-recognition model is 97% accurate. Give two questions you would ask before trusting the figure.
Unit 1 introduces the ethical frameworks; Unit 3 asks you to apply that thinking to the scoring step. A strong answer uses the word from the question (bias, transparency or accountability) and attaches one concrete example to it. More case-style practice like this is on the case-based questions page.
Q6. Written answers
Twelve original questions in the shapes the paper uses. Write your answer first, then open the model answer and check it against the points in bold, which is how an examiner reads it.
In class, each of these shapes is written to the clock, then marked on the shared screen point by point, so students see exactly which phrase earned the mark and which did not. Unit 2, the other heavy theory unit, is answered the same way on advanced concepts of modeling questions, and the cross-unit list is on CBSE Class 10 AI important questions.
Batch or personalised: you choose
Both formats teach Evaluating Models the same way: the idea, a worked example, then answers written and marked against the scheme. The batch keeps the whole syllabus moving on a fixed rhythm; one to one stays on Unit 3 until the metric questions stop costing marks. Monthly billing, no admission fee, stop at any month end.
Option 1 · Fixed batch timings
₹1,499
per month, two live classes a week
Option 2 · Choose your own timing
₹4,999
per month, one private class a weektwo private classes a week, at a time set with you
A student who follows the theory but freezes when asked to choose between precision and recall usually needs a few focused one to one sessions with many short scenarios. A student meeting Unit 3 for the first time does better in the batch, where Units 2 and 3 are taught in sequence and modelling makes sense before scoring. Fees appear in your own currency.
Studying outside India?
A CBSE school in Sharjah, Jeddah or Doha sits the same 417 paper, with the same 10 marks for Evaluating Models. These are the local times of the batch this winter.
| Where you live | Mon and Wed 9:00 PM IST | Best format |
|---|---|---|
| India (IST) every Indian city | 9:00 PM | Batch fits |
| UAE and Oman Dubai, Abu Dhabi, Sharjah, Muscat | 7:30 PM | Batch fits |
| Saudi Arabia, Qatar, Kuwait, Bahrain Riyadh, Jeddah, Dammam, Doha, Kuwait City, Manama | 6:30 PM | Batch fits |
| Nepal Kathmandu | 9:15 PM | Batch fits |
| Ethiopia and East Africa Addis Ababa and East Africa Time | 6:30 PM | Batch fits |
| Singapore and Malaysia Singapore, Kuala Lumpur | 11:30 PM | Choose 1-on-1 |
If the batch hour is awkward where you live, one to one runs at a time you pick. Family-specific details are on CBSE Class 10 AI online classes in the Gulf and abroad.
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The rest of the Class 10 series
Every page in the CBSE Class 10 AI (417) series, grouped by what you need: classes, each unit, question practice, notes and revision, and the exam itself.
ICSE Class 10 Computer Applications (Java): The Tue and Wed ICSE Java batch ICSE Computer Applications syllabus ICSE Java programs practice ICSE CA important questions
Questions about Unit 3
Evaluation is the final stage of the AI project cycle, where a trained model is tested on data it has not seen to check how reliable its predictions are. It uses measures such as accuracy, error, precision, recall and F1 score, and its result can send a project back to collect more data or try another model.
Unit 3, Evaluating Models, carries 10 of the 50 theory marks in the 417 curriculum for 2026-27, second only to Unit 2, Advanced Concepts of Modeling, at 11. In the 2025-26 sample paper it supplied six of the 24 objective items in the AI part, alongside written questions.
It is dividing a labelled dataset into a training set, which the model learns from, and a testing set, which is held back and used only to check the finished model. Because the model never saw the test data, its score there is a fair estimate of how it will do on new data.
The model has already seen those examples and may simply have memorised them. Its score would look excellent while hiding overfitting, so it would tell you nothing about how the model handles new cases. Only unseen test data gives an honest measure.
Error measures how far a prediction is from the actual value, while accuracy measures how close it is. For a number prediction, error rate is the error divided by the actual value, and accuracy is 1 minus the error rate, so the two always add up to 1.
Ask which wrong prediction hurts more. If a false alarm is costly, as when real emails go to spam, use precision. If a miss is costly, as when a disease or a fraud goes undetected, use recall. If both matter, especially with a rare class, use the F1 score.
Bias, transparency and accountability. The test data must represent every group the model will serve, the way a model was scored and its weak spots must be reported openly, and the people who chose the metric must take responsibility for its effects. Reporting accuracy honestly falls under transparency.
Not always. When one class is rare, a model that always predicts the common class can score very high accuracy while missing every case that matters. That is why Unit 3 also teaches precision, recall and the F1 score, and asks you to choose between them.
This page holds the concepts and written answers for Unit 3. Confusion matrix numericals with full working are on our separate numericals page, the formulas are collected on the 417 formula sheet, and objective items on the unit are in the class 10 AI MCQ bank.
Yes. It is taught in the Monday and Wednesday 9:00 PM IST batch, with written answers marked in class, or in personalised one to one at a time you choose. The monthly fee shown on this page, in your own currency, covers it. There is no admission fee and the first class is a free demo.
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In the free first class your child meets one Evaluating Models idea properly: a short accuracy and error table worked on screen, then a precision or recall scenario answered in writing and marked against the value points. Afterwards the mentor tells you which parts of Unit 3 look secure, which do not, and whether the batch or one to one is the better fit.
Want to see the whole subject first? Read the 417 syllabus explained.
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