A scatter diagram for 100 observations appears to show strong positive correlation. After one point recorded with the wrong unit is corrected, the positive correlation is noticeably weaker.
Explain why the original impression of the correlation was misleading.
State two checks that should be made before deleting any apparent outlier.
Explain why the corrected correlation still does not demonstrate causation.
105 exam-style questions on WJEC A Level Maths 2.2 Data presentation and interpretation, covering 2.2.1 Data presentation and interpretation, 2.2.2 Data presentation and interpretation, 2.2.3 Data presentation and interpretation, 2.2.4 Data presentation and interpretation, 2.2.5 Data presentation and interpretation, 2.2.6 Data presentation and interpretation, 2.2.7 Data presentation and interpretation, 2.2.8 Data presentation and interpretation, and 2.2 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.