Marine Science
Part 1: Box Plots
Box plots are often used to visually represent data in a range. They include important statistical information such as the median (the middle value), and interquartile range (the values that fall between the 25th and 75th percentile of the data).

Using the following average monthly sea surface temperatures from Anchorage, Alaska, we can make a box plot: the images as the charts

The blue box shows the interquartile range. The middle 50 percent of the values lie within this box. The bottom 25 percent are represented by the left “whisker” and the top 25 percent are represented by the right “whisker”. The vertical line in the interquartile range box represents the median (middle) value of 39.

The larger the interquartile range, the more spread out the values are. The interquartile range is useful because it helps us ignore outliers (values that are extremely low or high). It is interesting to note that the median value is not in the middle of our box plot; because the warmer temperatures are more spread out and the colder temperatures are closer together, the box plot appears skewed.

Now it’s your turn to make a box plot!

Using the National Oceanic and Atmospheric Administration (NOAA) website of coastal temperature data, choose a city (try to pick a city that has monthly data rather than bi-monthly data).
Then use an online graphing website such as meta-chart.com to make a box plot, making sure to enter all of the data accurately. Make sure to include an appropriate and descriptive title.
Using your data, compute the mean water temperature for your city. Is the mean above or below the median? What does this tell you about the data?
Submit your water temperature data along with your box plot and explanation.