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2.2 Data presentation and interpretation

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Question 40

The time taken, t t\,t minutes, for each of 50 employees to travel to work is recorded. The times are coded using

y=t−305\displaystyle y = \frac{t - 30}{5}y=5t−30​

For the 50 coded values,

∑y=120\sum y = 120∑y=120 and ∑y2=400.5\sum y^2 = 400.5∑y2=400.5

a.

Calculate the mean and the standard deviation of the coded values.

[3]
b.

Hence find the mean and the standard deviation of the times ttt.

[2]
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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