Answer the following questions with the SQL query that I need for the answer.

1. What is the average number of documents retrieved per participant? Note: write a single SQL query which gives you the answer.

2. List, in order from earliest to latest, the different dates (your SQL should return dates only, not times of day!) during which experimental data were collected and the number of experiment_data records collected on each of those dates. Again, use a single query!

a 101 yunistate.edu/ba371/reitsma/assignment assignes o participants table: -- - | Field Type --- username varchar(255) | user type varchar(10) 1 years int | low grade int high grade int on line varchar(10) on_line_sources | varchar(255) | location varchar(5) exp_condition int -- ---- --- This table contains the information for each of the experiment's participants - username: id of the participant. user_type: was the participant a student or a licensed teacher. years: years of teaching experience. - low_grade: lowest grade the participant teaches. - high grade: highest grade the participant teaches. - on_line: does the participant use on-line lesson materials? - on_line_sources: if so, which ones? location: Subject's US state. exp_condition: 1=list, 2=map. tasks table: | Field JUULIUL UL WILLY USEU Was lepi documents table: Field Type | username I varchar(255) | task i varchar(5) doc_type varchar(10) I used tool int relevant int motivational | concepts background | grade_level I hands on | attachments . ... SEE Participants were asked to search for documents on the web site as part of their tasks. Each row in the table - username: id of the participant task: id of the task the participant completed doc_type: the type of the found document. - used_tool attachments: opinion about the usefulness of the found document (1-6). experiment_data table: Field apce e CUTIE tasks table: Field - --- ---- --- - + username task confidence sim helpd | varchar(255) | varchar(5) int int +-.. This table lists the various tasks participants conducted during the experiment: - username: id of the participant. taskid of the task the participant completed. confidence: confidence that the participant had in having done the task well (1-6). sim_helpd: participant's opinion that the map or list (depending on which one they documents table: Field Type username yarchar255 Used TOOL LUCmen. Upun douu ule useless U U UUD o experiment_data table: Field Type int(11) host_ip varchar (20) referer varchar(255) file varchar(255) querystring varchar(255) timestamp datetime username varchar(255) source doc id int(11) dest_doc_id int(11) exp_condition | int(11) map action int(11) All of the participants' actions associated with the 'list' and 'map' interfaces - id: record id host_ip: IP of the machine from which the request came. referer: referring web page. file: requested web page. querystring any parameters passed in the request. timestamp: time of the request (one-second accuracy). username: id of the participant. source_doc_id: the id of the document from which the request/action i dest_doc_id: the id of the document resulting from the action. - exp_condition: 1=list, 2=map. map_action: type of map action executed