Systematic variation can be caused by two sources - your Question Blank 1 of 15 type your answer... variable and your Question Blank 2 of 15 type your answer... (extraneous variables). In a given experiment we try to minimize the variability imposed by the Question Blank 3 of 15 type your answer... and isolate the observed variability causes to the Question Blank 4 of 15 type your answer... variable. ----- Systematic Question Blank 5 of 15 type your answer... can be Question Blank 6 of 15 type your answer... by Question Blank 7 of 15 type your answer... (2) - your Question Blank 8 of 15 type your answer... (2) and your Question Blank 9 of 15 type your answer... (extraneous variables). In a given experiment we try to Question Blank 10 of 15 type your answer... the Question Blank 11 of 15 type your answer... imposed by the Question Blank 12 of 15 type your answer... and Question Blank 13 of 15 type your answer... the observed Question Blank 14 of 15 type your answer... causes to the Question Blank 15 of 15 type your answer... (2)