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how can i determine the mean using box plot? also can we know which series has the highest mean value ? enter image description here

Hasan
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  • Please tell us what the marks on these plots mean: there are many different conventions. According to the commonest one, the midline is the median and therefore there's no way you can determine the means or compare them. But maybe your midlines represent some other statistic? – whuber Sep 01 '20 at 18:48
  • yes the middle is the median and the others are the quartile and range – Hasan Sep 01 '20 at 18:52

1 Answers1

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A more common name is box-and-whisker plot, or just box plot.

The mean is not shown on either plot.

It is certainly between the minimum and maximum and likely to be between the median and the upper quartile if the distribution is right skewed and between the median and the lower quartile if the distribution is left skewed. Almost always, we need the original data too to read off the mean.

But watch out!

For example:

  1. Your data in this case appear to be integers between 1 and 10, in which case a histogram or dot plot will work better. Usually integer values mean that (a) the minimum and maximum are integers too (b) also the median and quartiles are likely to be integers too (or half-integers). The granularity of a discrete distribution with few distinct values is not caught well by such a plot.

  2. I note that 25% or more of Series B are 9 or 10, so the distribution is more complicated than a quick guess at the plots might seem to imply.

Nick Cox
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