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2 Statistics

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Question 238

The lifetimes x x\,x hours of 40 components are grouped below.

x0≤x<2020≤x<3030≤x<6060≤x<80frequency814126\begin{array}{c|cccc}x&0\leq x<20&20\leq x<30&30\leq x<60&60\leq x<80\\\hline\text{frequency}&8&14&12&6\end{array}xfrequency​0≤x<208​20≤x<3014​30≤x<6012​60≤x<806​​

a.

Calculate estimates of the mean and sample standard deviation.

[5]
b.

Explain two limitations of using these estimates to describe the original data.

[2]
Markscheme

2 Statistics Questions

  1. A Level
  2. /Maths
  3. /2 Statistics

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