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SQL Queries for Data Analytics

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Questions and Answers

What is recall in the context of information retrieval?

The ratio of relevant documents retrieved to the total number of relevant documents in the collection (correct)
The ratio of relevant documents retrieved to the total number of documents retrieved
The number of relevant documents retrieved
The ratio of documents retrieved to the total number of documents in the collection

What is the formula to calculate precision?

(Number of relevant documents retrieved) / (Total number of relevant documents)
(Total number of documents retrieved) / (Number of relevant documents retrieved)
(Total number of relevant documents) / (Number of relevant documents retrieved)
(Number of relevant documents retrieved) / (Total number of documents retrieved) (correct)

What is the purpose of indexing in information retrieval?

To facilitate efficient and quick retrieval of information (correct)
To improve recall
To reduce the number of relevant documents
To improve precision

What is the relationship between precision and recall?

They are inversely related (A) Signup and view all the answers

What is the formula to calculate recall?

(Number of relevant documents retrieved) / (Total number of relevant documents) (B) Signup and view all the answers

What is an index in the context of information retrieval?

A data structure that maps content to their locations or identifiers (A) Signup and view all the answers

What is the purpose of the 'AS' keyword in SQL?

To rename a column alias (B) Signup and view all the answers

What type of join returns all rows from the left table and the matched rows from the right table?

LEFT JOIN (C) Signup and view all the answers

What is the purpose of the 'GROUP BY' clause in SQL?

To group the result set by one or more columns (B) Signup and view all the answers

What is the purpose of the 'ORDER BY' clause in SQL?

To sort the result set in ascending or descending order (C) Signup and view all the answers

What type of join returns rows from both tables where the join condition is met?

INNER JOIN (C) Signup and view all the answers

What is the purpose of the 'COUNT(*)' function in SQL?

To count the number of rows in a table (C) Signup and view all the answers

What is the purpose of the sed command in the example?

To replace occurrences of 'sed' with 'awk' in the file (C) Signup and view all the answers

What is the main motivation behind working with data?

To predict the future (C) Signup and view all the answers

What is a datum according to the text?

A unit of information (B) Signup and view all the answers

What is the definition of Data Science according to the text?

The theory of principled prediction (A) Signup and view all the answers

What is the output of the sed command in the example?

The modified text printed to the standard output (A) Signup and view all the answers

What is the significance of the quote 'Those who cannot remember the past are condemned to repeat it'?

It underscores the importance of understanding the past (D) Signup and view all the answers

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