MLS-C01 · Question #152
A Machine Learning Specialist is developing a regression model to predict ticket sales for an upcoming concert. The historical ticket sales data consists of more than 1,000 records containing 20…
The correct answer is A. Drop the unusual records and replace the blank values with the mean value. The specialist needs to handle a small number of extreme, yet plausible, outliers and fill in missing values in numerical variables for a regression model. A common approach is to remove influential outliers and impute missing data with a central tendency measure.
Question
A Machine Learning Specialist is developing a regression model to predict ticket sales for an upcoming concert. The historical ticket sales data consists of more than 1,000 records containing 20 numerical variables. During the exploratory data analysis phase, the Specialist discovered 33 records have values for a numerical variable in the far right of the box plot's upper quartile. The Specialist confirmed with a business user that those values are unusual, but plausible. There are also 70 records where another numerical variable is blank. What should the Specialist do to correct these problems?
Options
- ADrop the unusual records and replace the blank values with the mean value
- BNormalize unusual data and create a separate Boolean variable for blank values
- CDrop the unusua records and fill in the blank values with 0.
- DUse unusual data and create a separate Boolean variable for blank values
How the community answered
(54 responses)- A83% (45)
- B2% (1)
- C11% (6)
- D4% (2)
Why each option
The specialist needs to handle a small number of extreme, yet plausible, outliers and fill in missing values in numerical variables for a regression model. A common approach is to remove influential outliers and impute missing data with a central tendency measure.
Dropping a small number of unusual, but plausible, records (33 out of 1000) can prevent them from disproportionately influencing a regression model sensitive to outliers. Replacing blank numerical values with the mean is a standard and effective imputation technique that preserves data points while providing a reasonable estimate for missing information.
Normalizing unusual data scales the values but does not inherently reduce the leverage or influence of outliers on a regression model. While creating a Boolean variable for blank values is a valid technique, it typically complements, rather than replaces, a primary imputation strategy.
While dropping unusual records might be acceptable, filling blank numerical values with 0 is often inappropriate unless 0 has a specific, meaningful interpretation for that variable, as it can otherwise introduce significant bias.
Using unusual data as-is without modification can negatively impact a regression model's performance due to its sensitivity to outliers. Similar to B, creating a Boolean variable for blanks is helpful but doesn't fully resolve the missing data problem without an imputation strategy for the original column.
Concept tested: Handling outliers and missing data in numerical variables
Source: https://scikit-learn.org/stable/modules/impute.html
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