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2.2 Data presentation and interpretation

2.2 Data presentation and interpretation

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Question 28

Twenty values have mean 12, and for these values ∑x2=2960\sum x^2 = 2960∑x2=2960.

One further value, ccc, is added. The mean of the resulting 21 values is 12.5.

a.

Find the value of ccc.

[2]
b.

Find the standard deviation of the 21 values.

[3]
c.

The standard deviation of the original 20 values is 2. Explain why the standard deviation of the 21 values is larger.

[1]
Markscheme

2.2 Data presentation and interpretation Questions

  1. A Level
  2. /Maths
  3. /2.2 Data presentation and interpretation

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.

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