The CO emissions, in g/km, of a random sample of 25 cars are recorded. The mean of the 25 recorded values is 0.28 g/km.
It is then discovered that one car's CO emission was recorded as 0.85 g/km when the correct value is 0.35 g/km. No other value is wrong.
For this question, a value is defined to be an outlier if it is more than two standard deviations from the mean.
Calculate the mean of the 25 corrected values.
The standard deviation of the 25 corrected values is 0.06 g/km. Determine whether the corrected value of 0.35 g/km is an outlier.
28 exam-style questions on AQA A Level Maths 2.1 K: Statistical sampling, covering 2.1.1 Populations, samples and sampling techniques. Each one has a worked solution and a mark scheme showing where the marks go.