Stem & Leaf Plots Examples

This stem and leaf plot represents the predicted high temperatures for New York City in the next 10 days.

5|7 represents a predicted temperature of 57 degrees Fahrenheit.

Use this plot to find the median of the data.

With this kind of plot, the data values are already in numerical order, which makes it much easier to find the median. If we cross out each pair of highest and lowest values until the middle becomes visible, we can find the median.  For example, the first pair of highest and lowest values is 70 and 57; the second pair is 69 and 59, and so on.

The median of this data is between 64 and 63.

The exact median is calculated by taking the mean of 64 and 63, which equals 63.5.  

This plot shows the top 20 final times for the two-man bobsled teams at the 2010 Winter Olympics.

3:26|65 represents a time of 3 minutes 26.65 seconds.

As you can see the difference between the gold medal winner and the bronze medal winner is less than 1 second (3:27.51 – 3:26.65 = 0.86 sec)!

Use this plot to find the mean time and the range for the top twenty bobsled teams.

To find the mean we must add each of the times together and divide by 20 scores. Since all of the times start with 3 min, when adding them together, we can just add up the seconds, and add the minutes back in at the end.

Now, add back in the 3 minutes we left out in that last step:
= 3 min 29.308 sec

The data ranges from 3:32.06 to 3:26.65.

Using the plot from Example 2, how many two-man bobsled teams finished in less than 3 minutes and 31 seconds and how many took longer to finish?

No teams finished in 3 minutes and 31 seconds. Adding up the number of teams above that line in the stem and leaf plot, there are 7 teams that finished in 3 minutes, 30 seconds, 5 teams that finished in 3 minutes 29 seconds, 1 team that finished in 3 minutes 28 seconds, 4 teams that finished in 3 minutes 27 seconds, and 2 teams that finished in 3 minutes 26 seconds. That makes 19 teams that finished in less time than 3 minutes and 31 seconds.

There is 1 team that finished with a time longer than 3 minutes and 31 seconds. The last team finished with 3 minutes and 32.06 seconds.