THE STEM AND LEAF PLOT

Steam and leaf plots are a method for showing the frequency with which certain classes of values occur. You could make a frequency distribution table or histogram for the values, or you can use a stem and leaf plot and let the numbers themselves to show pretty much the same information.

Example: 

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 make it’s 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

Example 2:

This plot shows the top 20 final times for the two-man bobsled teams at the 2011 winter Olympics

3:65 │ 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 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 minutes, 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

Questions that you can try:

1.Sam got his friends to do a long jump and got this results:

2.3, 2.5, 2.5, 2.7, 2.8, 3.2, 3.6, 3.6, 4.5, 5.0

Try to find the means and make the steam and leaf plot

GOODLUCK!😊😊😊