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Learn Understanding Data Quality | Data Cleaning Essentials
Data Preprocessing and Feature Engineering

bookUnderstanding Data Quality

When you work with machine learning, the quality of your data is one of the most important factors in building effective models. High-quality data allows algorithms to learn accurate patterns, while poor data can lead to misleading results, wasted resources, and unreliable predictions. Raw datasets almost always contain issues that must be addressed before you can trust the outcomes of your analysis.

Note
Definition: Data Quality

Data quality measures how accurately and completely a dataset reflects the real world. High-quality data is essential because machine learning models rely on accurate, consistent, and relevant information for reliable predictions.

Common data quality problems include missing values, where some entries in a dataset are empty; duplicate records, which can bias results or inflate the importance of certain data points; and outliers, which are values that are unusually high or low compared to the rest of the data. Other issues may involve inconsistent formatting, incorrect data types, or errors introduced during data collection. Each of these problems can distort the patterns that machine learning models try to learn, leading to poor performance or unexpected behavior.

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import pandas as pd # Load a sample dataset from seaborn import seaborn as sns df = sns.load_dataset('titanic') # Display the first few rows print("Head of dataset:") print(df.head()) # Show basic information about the dataset print("\nInfo:") print(df.info()) # Show summary statistics for numerical columns print("\nDescribe:") print(df.describe())
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Note
Interpreting Summary Statistics

When reviewing df.describe(), focus on minimum and maximum values, counts, and standard deviation. Unusual values or mismatched counts can reveal missing data, outliers, or inconsistent entries that need cleaning.

question mark

Which of the following is NOT a common data quality issue you might find in a raw dataset

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 1. ChapterΒ 1

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bookUnderstanding Data Quality

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When you work with machine learning, the quality of your data is one of the most important factors in building effective models. High-quality data allows algorithms to learn accurate patterns, while poor data can lead to misleading results, wasted resources, and unreliable predictions. Raw datasets almost always contain issues that must be addressed before you can trust the outcomes of your analysis.

Note
Definition: Data Quality

Data quality measures how accurately and completely a dataset reflects the real world. High-quality data is essential because machine learning models rely on accurate, consistent, and relevant information for reliable predictions.

Common data quality problems include missing values, where some entries in a dataset are empty; duplicate records, which can bias results or inflate the importance of certain data points; and outliers, which are values that are unusually high or low compared to the rest of the data. Other issues may involve inconsistent formatting, incorrect data types, or errors introduced during data collection. Each of these problems can distort the patterns that machine learning models try to learn, leading to poor performance or unexpected behavior.

1234567891011121314151617
import pandas as pd # Load a sample dataset from seaborn import seaborn as sns df = sns.load_dataset('titanic') # Display the first few rows print("Head of dataset:") print(df.head()) # Show basic information about the dataset print("\nInfo:") print(df.info()) # Show summary statistics for numerical columns print("\nDescribe:") print(df.describe())
copy
Note
Interpreting Summary Statistics

When reviewing df.describe(), focus on minimum and maximum values, counts, and standard deviation. Unusual values or mismatched counts can reveal missing data, outliers, or inconsistent entries that need cleaning.

question mark

Which of the following is NOT a common data quality issue you might find in a raw dataset

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 1. ChapterΒ 1
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