| 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 20×10=200 A1 N1
(ii) METHOD 1
variance is 36 A1
new variance is 36×100=3600 A1 N2
METHOD 2
new sd is 60 A1
new variance is 602=3600 A1 N2
[3 marks]
b(i) and (ii).
Examiners report
[N/A]
a(i) and (ii).
[N/A]
b(i) and (ii).
