The masses, x x\,x kg, of 40 cars have mean 1420 kg and standard deviation 180 kg. The masses are coded using
y=x−100020\displaystyle y = \frac{x - 1000}{20}y=20x−1000
Find the mean and the standard deviation of the coded values.
The median of the coded values is 20.5. Find the median mass.
Explain why the standard deviation of the coded values is smaller than 180.
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.