What is a box-and-wisker plot?

Answer 1

The first step in constructing a box-and-whisker plot is to first find the median, thelower quartile and the upper quartile of a given set of data. Example: The following set of numbers are the amount of marbles fifteen different boys own (they are arranged from least to greatest).18 27 34 52 54 59 61 68 78 82 85 87 91 93 100

• First find the median. The median is the value exactly in the middle of an ordered set of numbers. *68 is the median
• Next, we consider only the values to the left of the median: 18 27 34 52 54 59 61. We now find the median of this set of numbers. Remember, the median is the value exactly in the middle oa an ordered set of numbers. Thus 52 is the median of the scores less than the median of all scores, and therefore is the lower quartile.52 is the lower quartile
  • Now consider only the values to the right of the median: 78 82 85 87 91 93 100. We now find the median of this set of numbers. The median 87 is therefore called the upper quartile.87 is the upper quartile(*If you're finding the median in an ordered set with an even number of values, you must take the average of the two middle numbers. For example: 3, 5, 7, and 10. Add the two middle numbers. 5 + 7 = 12. Divided 12 by 2 to get the average. 12 / 2 = 6. Therefore 6 is the median for the ordered set of 3, 5, 7, and 10.)
    • You are now ready to find the interquartile range (IQR).The interquartile range is the difference between the upper quartile and the lower quartile. In our case the IQR = 87 - 52 = 35. The IQR is a very useful measurement. It is useful because it is less influenced by extreme values, it limits the range to the middle 50% of the values.
    35 is the interquartile range

    here is a sucessful site called Jen's Box and Whisker plot, and here is a example of a whisker plot from that very own site. because it

    so hard to describe! i hope you find this helpful good luck!!