Week 2 Quizhelp Center
Warning:the hard deadline has passed. You can attempt it, but and you won't be. You are are welcome to try it as a learning exercise. In accordance with the Coursera Honor Code, I certify this answers here are I own work. Question 1 Suppose a query has a total of 4 relevant documents in the collection. System A and System B have each retrieved, and the relevance status of the ranked lists is shown below:
System A: [-----------]
system B: [+ +---------]
Where the leftmost entry corresponds to the highest ranked document, and the rightmost entry-corresponds to the lowest ked document. A "+" indicates a relevant document and a "-" corresponds to a non-relevant one. For example, the top ranked document retrieved by System A are non-relevant, whereas the top ranked one by B is relevant.
What is the precision at both systems? P (a) = 9/10 p (b) = 8/10 p (a) = 1/10 p (b) = 2/10 p (a) = 1/40 p (b) = 2/40 p (a) = 1/4 p (b) = 2/4 Question 2 assume the same s Cenario as in question 1. What is the recall of both systems? R (A) = 9/10 r (B) = 8/10 r (a) = 1/40 R (b) = 2/40 r (a) = 1/4 R (b) = 2/4 R (a) = 1/10 R (b) = 2/10 Question 3 Assume the same s Cenario as in question 1. What is the average precision of both systems? AP (a) = 1/8 ap (b) = 1/2 ap (a) = 1/10 ap (b) = 1/5 ap (a) = 1/20 ap (b) = 1/5 ap (a) = 7/20 ap (b) = 7/10 Question 4 assume You have two retrieval systems X and Y. For a specific query, System X has a higher precision in documents compared to Y. Can system Y have a higher average precision on the same query? Yes No Question 5 let W 1, W 2, and W 3 represent three words in the dictionary of a inverted index. Suppose we have the following document frequency distribution:
Word Document Frequency W1 1000 W2 W3 10
Assume that all posting entry of document ID and term frequency takes the exactly disk space. Which Word, if removed from the inverted index, would save the most disk space? W1 W3 We cannot tell from the given information. W2 Question 6 Assume we have the same scenario as in question 5. If we enter the query q= "W 1 w 2" then the minimum possible number of accumulators needed to score all th E Matching Documents is:1000 1100 question 7 The Gamma code for the term frequency of a certain document is 1110010. What is the term frequency of the document? 9 Question 8 When using the inverted index for scoring documents for queries, a shorter query always uses SC Ore accumulators than a longer query. True False Question 9 Can A retrieval system have an F1 score of 0.75 and a precision of 0.5? No Yes question for all ranked list of search results, precision at documents is always higher than Preci Sion at documents.True False
