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Pandas and Data Wrangling
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Pandas and Data Wrangling

HardSQL · PostgreSQL

Problem

How would you use Pandas to solve a data problem using groupby and merge, and what ML theory concepts would you connect it to?

Translate the data manipulation into PostgreSQL using the provided evaluation and project tables. Include completed evaluations with non-null actual and predicted values in the error metrics.

Output

  1. One row per project, including projects without valid evaluations
  2. Columns: project_id, project_name, model_family, evaluation_count, mean_absolute_error
  3. Sort by mean absolute error descending, with null errors last, then project_id ascending

Schema

projects
ColumnTypeDescription
project_idPKINTUnique project identifier
project_nameVARCHAR(100)Project display name
model_familyVARCHAR(50)Model family evaluated for the project
model_evaluations
ColumnTypeDescription
evaluation_idPKINTUnique evaluation identifier
project_idINTProject associated with the evaluation
model_versionVARCHAR(30)Version used to generate the prediction
statusVARCHAR(20)Evaluation lifecycle status
actual_valueDECIMAL(10,2)Observed target value
predicted_valueDECIMAL(10,2)Model prediction
Tablesprojectsmodel_evaluations
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Your question is Pandas and Data Wrangling. Start with the requirements and the two tables in the Question tab.

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