1- A user issued a query on two search engines. The total number of web pages indexed by the two web pages is 200 web page. If the relevant web pages to the query were 20 . If IR1 returned 20 results, 10 were relevant, and 10 were not. IR2 returned 30 results, 20 were relevant and 10 were not. 1- Find recall, precision, and F1 for IR1? 2- Find recall, precision, and F1 for IR2 ? 3- Which IR is more accurate, in general ? 2- A user issued a query on a search engine. If the precision was 80% and recall was 40%. If the total number of web pages was 100 , and the total returned results were 20 . 2.1- How many relevant pages were returned in the results? 2.2- You want a search engine that returns only relevant web pages, even if not all relevant pages are returned. What evaluation measurement would you use (in general)