A box and whisker plot looks complicated, but it's really not. I used my veggie data to create the one illustrated below. Follow the steps below to make your own box and whisker plot. Take your data that is in order from least to greatest. (Like you used in the mean, mode, median, range and stem and leaf pages.
) My numbers: 1, 5, 7, 8, 8, 14, 17. Next, divide them up (while in order) into half. For example: 1, 5, 7, 8 and 8, 8, 14, 17. (Notice, that I had an odd number of data, 7, that can't be divided equally in half. So the middle number (the first 8) gets placed in each half. ) Now, take each half that you had and find the median for each.
(Remember from step three, the median is the middle number in a set of data. ) Congratulations! You now have everything you need to make your plot. You have: the lowest number - which is your "lower extreme," your highest number - which is your "upper extreme," your median - which you " ve already done from the mean, mode, median, and range page, the median of your lower half of your data - which is your "lower quartile," and the median of your higher half of your data - which is your "upper quartile." Next, you " ll make a number line for your data. You don't have to start at 1, just start at the "lower extreme" of your data. Then end with the "upper extreme" of your data. (DON'T FORGET TO INCLUDE ARROWS AT THE ENDS OF THE NUMBER LINE, because we know that the number system doesn't end or begin with our numbers.
) Next, you need to plot your lower extreme, upper extreme, lower quartile, upper quartile, and median. Do this by placing a dot above the number line where that number falls. Lastly, you have to draw your box and whiskers. To do this, connect the lower and upper quartiles by forming a box as illustrated below. Your median will fall somewhere within that box (it is ok if the median is the same number as one of your quartiles), connect it in the box by drawing a vertical line through the "plot" extending to the top and bottom of the box. Then from the lower extreme "plot" draw a line and connect it to the lower quartile "plot." (Just like connect the dots.
) Do the same for the upper extreme and upper quartile. Once you " ve finished drawing your box and whiskers, don't forget to label each of your plots.