Data Cleaning
All MATLAB topics∙ MATLAB
Data Cleaning explains data preparation and statistical evidence for measured observations. You will learn the exact MATLAB behavior, implementation rule, failure mode, and verification evidence for this lesson.
Syntax
% Topic: Data Cleaning
values = [12 18 21 25 29];
average = mean(values);Example
% Topic: Data Cleaning
values = [12 18 21 25 29];
average = mean(values);
spread = std(values);
fprintf('Mean: %.1f, Std: %.2f\n', average, spread);Expected Output
Mean: 21.0, Std: 6.44Line-by-line
| Line | Meaning |
|---|---|
% Topic: Data Cleaning | Builds the data or operation used by this MATLAB example. |
values = [12 18 21 25 29]; | Builds the data or operation used by this MATLAB example. |
average = mean(values); | Builds the data or operation used by this MATLAB example. |
spread = std(values); | Builds the data or operation used by this MATLAB example. |
fprintf('Mean: %.1f, Std: %.2f\n', average, spread); | Displays the calculated result. |
Real-World Uses
- 1Data Cleaning is used when a MATLAB workflow needs data preparation and statistical evidence for measured observations.
- 2Its exact implementation rule is: Preserve raw data and document missing-value, outlier, and transformation decisions.
- 3A practical data cleaning workflow defines inputs, units, expected output, and validation criteria.
- 4The main production risk is: Removing records or changing scales without documentation can bias conclusions.
- 5Teams evaluate it using data-quality traceability.
Common Mistakes
- 1Removing records or changing scales without documentation can bias conclusions.
- 2Implementing Data Cleaning without understanding data preparation and statistical evidence for measured observations.
- 3Ignoring dimensions, orientation, units, or missing values in the data cleaning workflow.
- 4Skipping the verification step: Compare row counts, distributions, missing values, and summary statistics before and after.
- 5Optimizing before collecting data-quality traceability.
Best Practices
- 1Preserve raw data and document missing-value, outlier, and transformation decisions.
- 2Document data preparation and statistical evidence for measured observations with the smallest useful MATLAB script, function, class, app, or model.
- 3Validate the dimensions, types, units, and assumptions required by Data Cleaning.
- 4Compare row counts, distributions, missing values, and summary statistics before and after.
- 5Use data-quality traceability to guide further changes.
How it works
- 1Data Cleaning relies on data preparation and statistical evidence for measured observations.
- 2Preserve raw data and document missing-value, outlier, and transformation decisions.
- 3Its main failure mode is: Removing records or changing scales without documentation can bias conclusions.
- 4Useful production evidence is data-quality traceability.
Implementation decisions
- 1Choose the owning script, function, class, app, live script, or Simulink model.
- 2Keep the data cleaning input shape, units, and output contract explicit.
- 3Select MATLAB data structures and toolboxes according to the exact operation.
- 4Document release, toolbox, hardware, and file dependencies.
Verification plan
- 1Compare row counts, distributions, missing values, and summary statistics before and after.
- 2Test normal, boundary, invalid, noisy, empty, or missing input where applicable.
- 3Compare one result with a manual calculation, analytical model, or trusted reference.
- 4Record data-quality traceability before and after changing the implementation.
Practice task
- 1Build the smallest working Data Cleaning example.
- 2Introduce this failure: Removing records or changing scales without documentation can bias conclusions.
- 3Correct it using this rule: Preserve raw data and document missing-value, outlier, and transformation decisions.
- 4Record data-quality traceability before and after the correction.
Quick Summary
- Data Cleaning works through data preparation and statistical evidence for measured observations.
- Preserve raw data and document missing-value, outlier, and transformation decisions.
- The key failure to avoid is: Removing records or changing scales without documentation can bias conclusions.
- Compare row counts, distributions, missing values, and summary statistics before and after.
- Measure success with data-quality traceability.
Interview Questions
Q1. What is Data Cleaning used for?
Answer: It is used for data preparation and statistical evidence for measured observations.
Q2. What implementation rule matters most?
Answer: Preserve raw data and document missing-value, outlier, and transformation decisions.
Q3. What failure is common with Data Cleaning?
Answer: Removing records or changing scales without documentation can bias conclusions.
Q4. How should Data Cleaning be verified?
Answer: Compare row counts, distributions, missing values, and summary statistics before and after.
Q5. What evidence shows that it works?
Answer: Collect and review data-quality traceability.
Quiz
Which practice best supports Data Cleaning?