Q. For the following set of data, find the population standard deviation, to the nearest hundredth.139,126,51,61,77,109,112
List data set & calculate mean: List the data set and calculate the mean (average).The data set is: 139,126,51,61,77,109,112.To calculate the mean, sum all the values and divide by the number of values.Mean = (139+126+51+61+77+109+112)/7Mean = 675/7Mean ≈96.43
Subtract mean & square: Subtract the mean from each data value and square the result.This step involves calculating the squared differences from the mean for each data point.(139−96.43)2=42.572≈1812.2049(126−96.43)2=29.572≈874.6849(51−96.43)2=−45.432≈2063.8849(61−96.43)2=−35.432≈1255.2849(77−96.43)2=−19.432≈377.5049(109−96.43)2=12.572≈158.0849(112−96.43)2=15.572≈242.5249
Sum squared differences: Sum the squared differences.Sum = 1812.2049+874.6849+2063.8849+1255.2849+377.5049+158.0849+242.5249Sum ≈7784.1743
Divide by data values: Divide the sum of squared differences by the number of data values to find the variance.Since we are calculating the population standard deviation, we divide by the total number of data points, which is 7.Variance =7784.1743/7Variance hickapprox1112.0249
Find standard deviation: Take the square root of the variance to find the population standard deviation.Standard Deviation = 1112.0249Standard Deviation ≈33.35
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