Which option is true about the outliers of the skewed dataset 5, 6, 6, 7, 7, 8,

8, 8, 9, 9, 14, 16?

• The outliers of the dataset are 14 and 16.
• The only outlier of the dataset is 16.
• There are no outliers in the dataset.
• The outliers of the dataset are 5, 14, and 16.

1 answer

To determine the outliers from the skewed dataset \(5, 6, 6, 7, 7, 8, 8, 8, 9, 9, 14, 16\), we can use the IQR (Interquartile Range) method.

  1. Order the dataset (not needed here, but it's given): \[ 5, 6, 6, 7, 7, 8, 8, 8, 9, 9, 14, 16 \]

  2. Find Q1 (the first quartile) and Q3 (the third quartile):

    • The median (Q2) is the average of the 6th and 7th values: \[ Q2 = \frac{8 + 8}{2} = 8 \]
    • For Q1, the lower half of the data is \(5, 6, 6, 7, 7\): \[ Q1 = 6 \]
    • For Q3, the upper half of the data is \(8, 9, 9, 14, 16\): \[ Q3 = 9 \]
  3. Calculate the IQR: \[ \text{IQR} = Q3 - Q1 = 9 - 6 = 3 \]

  4. Determine the lower and upper bounds for outliers:

    • Lower bound = \(Q1 - 1.5 \times \text{IQR} = 6 - 1.5 \times 3 = 6 - 4.5 = 1.5\)
    • Upper bound = \(Q3 + 1.5 \times \text{IQR} = 9 + 1.5 \times 3 = 9 + 4.5 = 13.5\)
  5. Identify outliers:

    • Any data point less than 1.5 or greater than 13.5 is considered an outlier.
    • In the dataset, the values \(14\) and \(16\) are greater than \(13.5\), making them outliers.
    • The value \(5\) is not considered an outlier since it is greater than \(1.5\).

Based on this analysis, the correct statement is:

  • The outliers of the dataset are 14 and 16.