Oil spills as of 2010. Data from the International Tanker Owners Pollution Federa- tion Limited give the cause of spillage for 460 oil tanker accidents resulting in spills of more than 700 tons from 1970-2010 (www.itopf.com). Results are summarized in the table below. Cause of spill Number of spills Collisions 132 Groundings 160 Hull Failures 34 Fire & Explosions 37 Loading/Discharging 55 Other/Unknown 42 (a) What is the variable in this study? (b) Is this qualitative or quantitative data? (c) The following is a barplot of the results 150 100 - Number of Spills 50 Collisions Groundings Hull Failures Fire & Explosions Other Unknown Loading Discharging Cause of spill What (informal) inference can you draw from the graph? (in no more than two sentences).The effect of protective headgear on head injuries and concussions in ado- lescent football (soccer) players (Br J Sports Med. 2008 Feb;42(2):110-5) In- vestigators examined the effects of protective headgear in adolescent soccer players. Participants were soccer players aged 12-17 years from clubs in Ontario. A question- naire examining the 2006 soccer season using self-reported symptoms. There were 278 participants, of which 216 reported not using headgear while playing and 52 reported using headgear while playing. Ten athletes could not reliably be classified as wear- ing or not wearing headgear. The following table provides the distribution of players cross-classified by position and whether or not they use headgear. Position No headgear Headgear Defense 68 19 Forward/Striker 13 13 Goalkeeper 20 6 Midfield 85 14 Headgear in Youth Soccer No Headgear Headgear Frequency Defender Forward/Striker Goalkeeper Midfielder (a) What (informal) inference can you draw from the graphs about the use of head- gear? (in no more than two sentences)