Notes 7-1E Stem and Leaf Plots Name - Deerlake Middle School

Notes 7-1E Stem and Leaf Plots
Name _________________________ Pd. _____
A stem and leaf plot is a display that, unlike histograms, shows all the individual data values. From the
display, the greatest, least, and median values can be seen.
In a stem and leaf plot, the data pieces are organized from least to greatest. The digits of the least place value
usually form the leaves, and the next place value digits form the stems.
How many tens are in 17
How many tens are in 23
How many tens are in 6
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How many tens are in 389 _________________
How many tens are in 102 _________________
The answers you just gave would be the stems in a stem and leaf plot, and the ones digits would be the
leaves. If there is no data for a particular stem, the stem is usually still included but it has no leaves.
Measures of central tendency are numbers that describe a data set and include the mean, median, and
mode. The range is the difference between the greatest and least numbers in a data set. The measures of
central tendency can be affected by an extreme value, called an outlier.

The stem and leaf plot shows the number of points scored by a high school basketball player. Which
measure of central tendency is most affected by the outlier

With all the types of data displays we have discussed, a survey must be taken in order to have data. In a
survey, data is collected about a specific group of people, called a population. . A smaller group is chosen from
the population, and this group is called a sample. . A sample is chosen to represent the population as a whole,
and the sample should be chosen without bias.
Bias: favoring one group over another; leaning one way based on prejudice. Conducting a survey with bias
can encourage the outcome to go a certain way. For a sample to accurately reflect an entire population, the
sample should be unbiased.
Determine whether each of the following conclusions is valid and explain your answer.
Every tenth student who walked into the cafeteria was surveyed to determine his or her favorite lunch. Out of 40
students, 19 students stated that they liked the burgers best. The cafeteria staff concluded that about 50% of the
students like burgers best.
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Janet surveyed the student athletes of the girls’ field hockey team to determine which sports teenagers like best.
Of these, 65% said that they like field hockey best. Janet concluded that over half of all teenagers like field hockey best.
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