Analysis of several plant-food preparations for potassium ion yielded the following data: Sample Percent 1 6.02, 6.04, 5.88, 6.06, 6.03 2 7.48, 7.47, 7.25 3 3.90, 3.96, 4.16, 4.17 The preparations were randomly drawn from the same population. (Use a spreadsheet to complete this question.) Find the mean and standard deviation for each sample. Sample 1 Mean = = Sample 2 Mean = = Sample 3 Mean = = Obtain the pooled value . = Why is a better estimate of than the standard deviation from any one sample? The pooled standard deviation uses a larger number of data points and can disregard fluctuations that arise because of sample selection and sample preparation. The pooled standard deviation involves more sophisticated model of data distribution and thus allows a more precise estimation of variation. The pooled standard deviation uses a larger number of data points and can reflect variations that arise because of sample selection and sample preparation. The pooled standard deviation provides more profound insight in the data distribution.