A-LevelMathematicsProbability and statistics9709/52 · May/June 2022 · Q13 Marks
For n values of the variable x, it is given that Σ(x – 200) = 446 and Ex = 6846.
- (a)Find the value of n.[3]
Mark scheme
Marking points from the official mark scheme (May/June 2022). The mark or mark type is shown in brackets.
- B1 Forming a correct 3-term (linear) equation from Σx, Σ200 and ∑(x−200). Accept 6846-200n = 446 ΟΕ. Condone 1 sign error.
- B1 SOI [Σ200 = 200n]
- B1 WWW [200n = 6846-446 = 6400] n = 32
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