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How do Boxplots work?

A box and whisker plot—also called a box plot—displays the five-number summary of a set of data. In a box plot, we draw a box from the first quartile to the third quartile. A vertical line goes through the box at the median. The whiskers go from each quartile to the minimum or maximum.

How do box and whisker plots work?

In a box and whisker plot:

  1. the ends of the box are the upper and lower quartiles, so the box spans the interquartile range.
  2. the median is marked by a vertical line inside the box.
  3. the whiskers are the two lines outside the box that extend to the highest and lowest observations.

Can you determine standard deviation from a box plot?

In a somewhat similar fashion you can estimate the standard deviation based on the box plot: the standard deviation is approximately equal to the range / 4. the standard deviation is approximately equal to 3/4 * IQR.

Can you tell mean from Boxplot?

In fact, even though the box plot does not directly contain the mean (it only shows the median) it is possible to estimate whether the mean is less than or greater than the median by looking whether the box plot is skewed to the left or to the right.

What is the difference between a box plot and a dot plot?

Dot plots show all values in the set. Box plots show a “five statistical summary” of the data set, dividing the data into quarters (25%). From left to right on the diagram: minimum, first quartile, median (or second quartile), third quartile, and maximum. Outliers, when present, are shown as a separate dot or asterisk.

What measure of central tendency do we primarily use with tables?

The mean is the most commonly-used measure of central tendency. When we talk about an “average”, we usually are referring to the mean. The mean is simply the sum of the values divided by the total number of items in the set.

What is the most reliable central tendency?

The mean is the most frequently used measure of central tendency because it uses all values in the data set to give you an average. For data from skewed distributions, the median is better than the mean because it isn’t influenced by extremely large values.