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2.2.3 Central tendency, variation and standard deviation

2.2.3 Central tendency, variation and standard deviation

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Question 11

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

2.2.3 Central tendency, variation and standard deviation Questions

  1. A Level
  2. /Maths
  3. /2.2.3 Central tendency, variation and standard deviation

39 exam-style questions on AQA A Level Maths 2.2.3 Central tendency, variation and standard deviation. Each one has a worked solution and a mark scheme showing where the marks go.

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