Q. For the following set of data, find the sample standard deviation, to the nearest thousandth.59,68,40,56,36,70,20
Calculate Mean: List the data set and calculate the mean (average).The data set is: 59,68,40,56,36,70,20.To find the mean, add all the numbers together and divide by the number of data points.Mean = (59+68+40+56+36+70+20)/7Mean = 349/7Mean = 49.857
Calculate Squared Deviations: Subtract the mean from each data point and square the result.This will give us the squared deviations from the mean.Squared deviations:(59−49.857)2=83.724(68−49.857)2=329.724(40−49.857)2=97.724(56−49.857)2=37.724(36−49.857)2=193.724(70−49.857)2=406.724(20−49.857)2=889.724
Add Squared Deviations: Add all the squared deviations together.Sum of squared deviations = 83.724+329.724+97.724+37.724+193.724+406.724+889.724Sum of squared deviations = 2039.068
Calculate Variance: Divide the sum of squared deviations by the number of data points minus one to find the variance.Since we have 7 data points, we subtract 1 to get 6 (n−1=7−1=6).Variance = 2039.068/6Variance = 339.845
Calculate Standard Deviation: Take the square root of the variance to find the sample standard deviation.Sample standard deviation = 339.845Sample standard deviation ≈18.435 to the nearest thousandth.
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