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Date None Specimen Marks available 2 Reference code SPNone.1.sl.TZ0.4
Level SL only Paper 1 Time zone TZ0
Command term Write down Question number 4 Adapted from N/A

Question

A data set has a mean of 20 and a standard deviation of 6.

Each value in the data set has 10 added to it. Write down the value of

(i)     the new mean;

(ii)    the new standard deviation.

[2]
a(i) and (ii).

Each value in the original data set is multiplied by 10.

(i)     Write down the value of the new mean.

(ii)    Find the value of the new variance.

[3]
b(i) and (ii).

Markscheme

(i) new mean is \(20 + 10 = 30\)     A1     N1

(ii) new sd is 6     A1     N1

[2 marks]

a(i) and (ii).

(i) new mean is \(20 \times 10 = 200\)    A1     N1

(ii) METHOD 1

variance is 36     A1

new variance is \(36 \times 100 = 3600\)     A1     N2

METHOD 2

new sd is 60     A1

new variance is \({60^2} = 3600\)     A1     N2

[3 marks]

b(i) and (ii).

Examiners report

[N/A]
a(i) and (ii).
[N/A]
b(i) and (ii).

Syllabus sections

Topic 5 - Statistics and probability » 5.2 » Effect of constant changes to the original data.

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