For 30 observations, the recorded summary statistics are ∑x=600\sum x=600∑x=600 and ∑x2=13200\sum x^2=13200∑x2=13200. A value of 20 was incorrectly recorded as 40.
Find the corrected values of ∑x \sum x\,∑x and ∑x2\sum x^2∑x2.
Calculate the corrected variance.
278 exam-style questions on CCEA A Level Maths 2.5 Data presentation and interpretation, covering 2.5.1 Data presentation and interpretation, 2.5.2 Data presentation and interpretation, 2.5.3 Data presentation and interpretation, 2.5.4 Data presentation and interpretation, 2.5.5 Data presentation and interpretation, 2.5.6 Data presentation and interpretation, 2.5.7 Data presentation and interpretation, 2.5.8 Data presentation and interpretation, 2.5.9 Data presentation and interpretation, and 2.5 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.