30 people ran a race and their race times, xxx, were recorded.
For these people ∑x=450∑x2=7020\sum x = 450 \quad \sum x^2 = 7020∑x=450∑x2=7020
Calculate the mean.
Hence, calculate the standard deviation for these data, giving your answer to 3 significant figures.
96 exam-style questions on Edexcel A Level Maths Measures of Location and Spread, covering 2.1 Measures of Central Tendency, 2.2 Other Measures of Location, 2.3 Measures of Spread, 2.4 Variance and Standard Deviation, and 2.5 Coding. Each one has a worked solution and a mark scheme showing where the marks go.