When reviewing a box plot, an outlier is defined as a data point that is located outside the whiskers of the box plot. Step 3: Look for potential outliers (see above image) Larger ranges indicate wider distribution, that is, more scattered data. This shows the range of scores (another type of dispersion). Next, look at the overall spread as shown by the extreme values at the end of two whiskers. The longer the box the more dispersed the data. Step 2: Compare the interquartile ranges and whiskers of box plotsД¬ompare the interquartile ranges (that is, the box lengths), to examine how the data is dispersed between each sample. If the median line of a box plot lies outside of the box of a comparison box plot, then there is likely to be a difference between the two groups. Note, although box plots have been presented horizontally in this article, it is more common to view them vertically in research papersД¬ompare the respective medians of each box plot. This is the box plot showing the middle 50% of scores (i.e., the range between the the lower 25% of scores and the upper 25% of scores). The upper and lower whiskers represent scores outside the middle 50% (i.e. The highest score, excluding outliers (shown at the end of the right whisker).

Seventy-five percent of the scores fall below the upper quartile value (also known as the third quartile).

Half the scores are greater than or equal to this value and half are less. The median marks the mid-point of the data and is shown by the line that divides the box into two parts (sometimes known as the second quartile). Twenty-five percent of scores fall below the lower quartile value (also known as the first quartile). The lowest score, excluding outliers (shown at the end of the left whisker). Box plots visually show the distribution of numerical data and skewness through displaying the data quartiles (or percentiles) and averages.Д«ox plots show the five-number summary of a set of data: including the minimum score, first (lower) quartile, median, third (upper) quartile, and maximum score. a) Make a box-and-whisker plot for the following data (snowfall, in inches, of the top ten snowiest cities. In descriptive statistics, a box plot or boxplot (also known as box and whisker plot) is a type of chart often used in explanatory data analysis. The two parts of the box and two whiskers.

Parts of a box and whisker plot