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:

TABLE Average sea surface temperatures
Anchorage, AK
January 31
February 31
March 32
April 34
May 44
June 54
July 58
August 57
September 53
October 44
November 34
December 32
Box and whisker plot with whiskers at 31 and 58, box running from 32 to 54, and median of 39
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.
Part 2: Histogram
A histogram is a display that groups data into ranges and shows their frequency. Below is a histogram of box plots (displayed vertically) that show the relationship between lightning activity and sea surface temperature (in Celsius) in the Mediterranean Sea over an eight-year period. Use the histogram to answer the following questions.

Histogram shows positive correlation between sea surface temperature and lightning strokes in the Mediterranean Sea over an eight-year period
Notice the median line in green and the mean line in purple. Why is the median line lower and more stable than the mean line?
Which sea surface temperature (in Celsius) saw the most amount of lightning strokes?
Why do you think the interquartile ranges of the box plots become bigger as the sea surface temperature increases?
Looking at the histogram as a whole, what conclusions can you draw about sea surface temperature, lightning strokes, and climate change?