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Explore how coding can simplify numerical analysis with large data sets by manipulating values and calculating mean and standard deviation. Gain insights on changes in results and understand coding effects.
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S1 Coding Using coding to make numbers easier to work with when data values are large
Mean and Standard Deviation Calculate the mean and standard deviation of the following data set 3,10,15,7,8 Add 3 to each of the numbers and recalculate the mean and standard deviation Subtract 2 from each of the numbers and recalculate the mean and standard deviation Multiply each of the numbers by 10 and recalculate the mean and standard deviation Divide each of the numbers by 2 and recalculate the mean and standard deviation
Solutions What do you notice about the coded results compared to the original results? Why does this happen?
Example 1 A data set has been coded using y=x/10. The standard deviation is 1.41 Find the standard deviation of the original data. 1.41 x 10 = 14.1
Example 2 A data set has been coded using y=x-20. The standard deviation is 3.641 Find the standard deviation of the original data. 3.641 as the standard deviation does not change
Example 3 A data set has been coded using y=x+100. 2 The standard deviation is 12.342 Find the standard deviation of the original data. 24.684 Adding 100 has no effect but the division by 2 has halved the standard deviation
σ² =798 – 140² = 4.82 30 30 E.G. 4 Time taken to complete reading a paper Σf=30 Σfy=140 Σfy² =798 Coded σ =2.19596 Original σ =2195.96