2nd October 2019

r-statistics
15

What are outliers on a box plot?

An outlier is an observation that is numerically distant from the rest of the data. When reviewing a boxplot, an outlier is defined as a data point that is located outside the fences (“whiskers”) of the boxplot (e.g: outside 1.5 times the interquartile range above the upper quartile and bellow the lower quartile).

People also ask, how do you find the upper and lower fences?

Step 2: Insert the values from Step 1 into the formulas and solve:
  1. Lower inner fence: Q1 – (1.5 * IQR) = 540 – (1.5 * 463) = -154.5.
  2. Upper inner fence: Q3 + (1.5 * IQR) = 1003 + (1.5 * 463) = 1697.5.
  3. Lower outer fence: Q1 – (3 * IQR) = 540 – (3 * 463) = -849.
  4. upper outer fence: Q3 + (3 * IQR) = 1003 + (3 * 463) = 2392.

What is an upper and lower fence?

The Lower fence is the "lower limit" and the Upper fence is the "upper limit" of data, and any data lying outside this defined bounds can be considered an outlier. LF = Q1 - 1.5 * IQR.