Σx=170,Σx2=2830 increase in Σx=10, then Σx′=170+10=180 Increase in Σx2=900−400=500 then Σx′2=2830+500=3330 Variance =n1Σx′2−(n1Σx′)2 =151×3330−(151×180)2=222−144=78
In an experiment with 15 observations on x, the following results were available: Σx2=2830,Σx=170 One observation that was 20 was found to be wrong and was replaced by the correct value 30 . The corrected variance is
Held on 30 Apr 2003 · Verified 6 Jul 2026.
8.33
78.00
188.66
177.33
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