Lesson 2'5 Statistics: Displaying and Analyzing Data

1
Lesson 2.5 Statistics Displaying and Analyzing
Data

• Key Terms
• Line plot- a number line labeled with a scale to
  include all the data with an x placed above the
  data point each time it occurs
• Frequency- how often a piece of data occurs
• Stem-and-leaf plot- a system used to separate
  data into two numbers that are used to form a
  stem and leaf
• Measures of Central Tendency-numbers or pieces of
  data that represent the whole set of data
  (Basically find the mean, median, and mode and
  see which ones best represent the data.)

2
Making a Line Plot

• Ex. 2 The speeds (mph) of 20 of the fastest land
  animals are listed below.
• 45, 70, 43, 45, 32, 42, 40, 40, 35, 50, 40, 35,
  61, 48, 35, 32, 50, 36, 50, 40
• Make a line-plot for the data
• Which speed occurs most frequently?

3
Create a Stem-and-Leaf Plot

• Ex. 3 Use the data below to make a stem-and-leaf
  plot
• 108, 104, 86, 82, 80, 72, 70, 62, 64, 68, 84, 64,
  98, 96, 98, 103, 87, 65, 83, 79, 97, 96, 112, 62,
  80, 62, 83, 76, 66, 97
• Stem Leaf

4
Measuring Central Tendency

• Let's look at the previous answer
• Stem Leaf
• 6 2 2 2 4 4 5 6 8
• 7 0 2 6 9
• 8 0 0 2 3 3 4 6 7
• 9 6 6 7 7 8 8
• 10 3 4 8
• 11 2
• Find the mean, median, and mode?
• What measure of central tendency best represents
  the data?

5
Measuring Central Tendency

• Let's look at the previous answer
• Stem Leaf
• 6 2 2 2 4 4 5 6 8
• 7 0 2 6 9
• 8 0 0 2 3 3 4 6 7
• 9 6 6 7 7 8 8
• 10 3 4 8
• 11 2
• What measure of central tendency best represents
  the data?
• Extremely high or low values can affect the mean,
  while not affecting the median or mode
• A value with high frequency can call the mode to
  be misleading
• When data is clustered with few values separated
  from the cluster can cause the median to be too
  low or too high.