Stem and Leaf Plots

Stem and Leaf Plots

In this presentation, you will get an overview of when to make stem and leaf plots, how to construct them as well as some practice in working with them.

​When do we use stem and leaf plots?

• Our data is quantitative

• We want to visualize each specific data value​ as much as possible

​How are stem and leaf plots and histograms similar/different?

• ​Both display quantitative data

• ​Both help us visualize the distribution of the data (turn the stem and leaf plot on its side)

• ​Stem and Leaf plots display each raw data value (or as close as possible), histograms group data into bins (classes).

• ​Stem and Leaf Plots are great for smaller data sets, histograms are much more useful for larger data sets.

​How do we make Stem and Leaf Plots?

• Break the digits into two parts, left values are stems, rightmost values are leaves

• Right values must only contain one digit, this becomes important when work with data that has more than two digits

• ​Making the stems

  • ​Divide the digits of each data value into two parts. The left parts are called the stem and the rightmost part is called the leaf.

  • ​Supply 0’s as appropriate so that all stems have the same number of digits.

​​How do we make Stem and Leaf Plots cont.

• Align all stems in a vertical column from smallest to largest. Draw a vertical line to the right of all the stems

• ​Place all the leaves with the same stem on the same row as the stem, and arrange the leaves in increasing order.

• ​Use a key to indicate the magnitude of the numbers in the display. We include the decimal position or indication of truncating in the key (if there are decimals or truncating) rather than with the stems or leaves.

• ​Create a proper title summarizing your data.

​Note:

• ​Pg. 62 in your Stats book has an excellent summary of the process of making stem and leaf plots.

Multiple Choice

How many games did the team play?

• 15
• 12
• 24
• 14

Multiple Choice

How many students scored a 100 on the test?

• 0

• 2

• 6

• 1

Multiple Choice

How many students scored more than 80%?

• 10

• 13

• 7

• 15

Multiple Choice

What is wrong with this stem and leaf diagram?

• Nothing- it's all correct.

• The order.

• It's missing a key.

• The title.

Multiple Choice

Which data set goes with this stem-and-leaf plot?

• 41,52,57,58,65,66,70,75,78,78,78,80,80,95

• 41,52,56,58,66,70,75,78,78,78,80,80,95,56

• 41,52,57,58,65,66,70,75,78,78,78,78,80,80

• 52,52,57,58,65,66,70,75,78,78,78,80,80,95

Multiple Choice

What is the median of data?

• 53

• 54

• 97

• 62

Multiple Choice

What percentage of the players had less than 50 digs?

• 60%

• 33.3%

• 40%

• 6.7%

Multiple Choice

Is a histogram the same as a bar graph?

• Yes, because they both use intervals.
• No, because a histogram displays numerical data while a bar graph displays categorical data.
• Yes, because they both use bars to display data.
• No, because a histogram displays categorical data while a bar graph displays numerical data.

Multiple Choice

This is the test scores for two different classes. WHICH class has more students?

• 2009 class

• 2010 class

• neither

• Same

Multiple Choice

This is the test scores for two different classes. Which class has a greater median?

• 2009 class

• 2010 class

• neither

• Same

Multiple Choice

This is the home runs for each member of these teams. Which team has the greater max?

• Mets

• Phillies

• Neither

• Same

Multiple Choice

Describe the shape of the graph

• Bimodal

• Multimodal

• Uniform

• Unimodal

Multiple Choice

Which of the following is not a type of graph for displaying quantitative data?

• histogram

• stemplot

• bar graph

Multiple Choice

How many cities have temperatures between 70 degrees and 99 degrees?

• 44
• 34
• 26
• 62

Multiple Choice

The histogram displays the number of hours of TV watched last week? How would you describe the shape of his distribution?

• Unimodal and skewed left

• Unimodal and skewed right

• Unimodal and symmetric

Multiple Choice

How would you describe the shape of this histogram?

• relatively symmetric

• skewed right

• skewed left

• uniform

Multiple Choice

What is the range of the Stem-and-Leaf Plot?

• 79

• 40

• 9

• 39