Select the outlier in the data set.29,39,49,68,83,95,99,744If the outlier were removed from the data set, would the mean increase or decrease?Choices:(A)increase(B)decrease
Q. Select the outlier in the data set.29,39,49,68,83,95,99,744If the outlier were removed from the data set, would the mean increase or decrease?Choices:(A)increase(B)decrease
Calculate Mean: Calculate the mean of the data set.Mean = (29+39+49+68+83+95+99+744)/8Mean = (1106)/8Mean = 138.25
Calculate Standard Deviation: Calculate the standard deviation of the data set.First, find the squared differences from the mean for each data point.Squared differences: (29−138.25)2, (39−138.25)2, (49−138.25)2, (68−138.25)2, (83−138.25)2, (95−138.25)2, (99−138.25)2, (744−138.25)2Calculating each: 11934.5625, 9801.0625, (39−138.25)20, (39−138.25)21, (39−138.25)22, (39−138.25)23, (39−138.25)24, (39−138.25)25Sum of squared differences: (39−138.25)26Sum of squared differences = (39−138.25)27Variance = Sum of squared differences / (number of data points - 1)Variance = (39−138.25)28Variance = (39−138.25)29Standard deviation = (49−138.25)20Standard deviation (49−138.25)21Standard deviation (49−138.25)22
Identify Outliers: Use the standard deviation to determine if there are any outliers.Typically, an outlier is a data point that is more than 1.5 times the interquartile range (IQR) above the third quartile or below the first quartile. However, since we do not have the quartiles, we can consider a data point that lies more than 3 standard deviations from the mean as an outlier.Outlier threshold: Mean ±3× Standard deviationLower threshold: 138.25−3×239.71≈−580.88 (which is not possible since all data points are positive)Upper threshold: 138.25+3×239.71≈857.38The data point 744 is above the upper threshold and is considered an outlier.
Effect of Removing Outlier: Determine the effect on the mean if the outlier is removed. Removing the outlier will decrease the sum of the data set without significantly reducing the number of data points, which will result in a lower mean.
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