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How many samples do you need for a Boxplot?
Whereas histograms require a sample size of at least 30 to be useful, box plots require a sample size of only 5, provide more detail in the tails of the distribution and are more readily compared across three or more samples. Several enhance- ments to the basic box plot can render it even more informative.
Does Boxplot show sample size?
No indication of sample size: Though you can use box plots on non-parametric data, it is best to have a sample size of at least 20 (some might even say 30). Remember: the size of each section in a box plot shows how widely spread a data range is; it says nothing about the quantity of the group.
What is the minimum for a box plot?
A box and whisker plot—also called a box plot—displays the five-number summary of a set of data. The five-number summary is the minimum, first quartile, median, third quartile, and maximum.
How many points is a Boxplot?
A box plot is constructed from five values: the minimum value, the first quartile, the median, the third quartile, and the maximum value. We use these values to compare how close other data values are to them.
Can a Boxplot miss a whisker?
For a box-and-whisker plot you order the data numerically from smallest to largest and find the lower quartile, median and upper quartile. The median is 2, the lower quartile (the median of the values less than the median) is 1 and the upper quartile is 3. Thus the box extends from 1 to 3 are there are no whiskers.
What is the minimum ” recommended ” sample size for boxplots?
Boxplots for different sample sizes What is the minimum “recommended” sample size to generate boxplots? If I’m comparing different methods and each method has a different sample size, is it fine to use boxplots for this comparison? If not, what is the best way to compare methods with different sample sizes?
How many observations do you need for a boxplot?
[I thought I had written an answer to the first question but I can’t locate one.] With 5 or fewer observations, you might as well just plot the actual points.
How to compare quantile plots to boxplots?
You might compare quantile plots, perhaps, or (as Nick Cox has suggested on at least one of his answers, but which I also can’t locate right now — edit: see here) you might combine such a plot with a boxplot by plotting the quantile plot under the boxplot. Thanks for contributing an answer to Cross Validated!
How to interpret the results of a boxplot?
If your boxplot has groups, assess and compare the center and spread of groups. Look for differences between the centers of the groups. For example, this boxplot shows the thickness of wire produced by four suppliers. The median thicknesses for some groups seem to be different.