Q. Select the outlier in the data set.8,85,87,89,90,91,92,94,98
Arrange Data Set: Arrange the data set in ascending order.The data set is already in ascending order: 8,85,87,89,90,91,92,94,98.
Calculate IQR: Calculate the interquartile range (IQR) of the data set.First, find the median (Q2), which is the middle value of the data set. Since there are 9 numbers, the median is the 5th number: 90.Next, find Q1, the median of the lower half. The lower half is 8, 85, 87, 89. The median of this half is the average of 85 and 87: 91.Then, find 92, the median of the upper half. The upper half is 93, 94, 95, 96. The median of this half is the average of 94 and 95: 99.Now, calculate the IQR: 50.
Determine Boundaries: Determine the outlier boundaries.The lower boundary is Q1−1.5×IQR=86−1.5×7=86−10.5=75.5.The upper boundary is Q3+1.5×IQR=93+1.5×7=93+10.5=103.5.Any data point below 75.5 or above 103.5 is considered an outlier.
Identify Outliers: Identify any outliers in the data set. The value 8 is below the lower boundary of 75.5, so it is an outlier.
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