AP Stats Section 1.1 Part 2

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AP Stats Section 1.1 Part 2

• Histograms
• CUSS

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Histograms

• Used to show the distribution of one quantitative
  variable.
• Similar in appearance to a bar chart, but no
  gaps.
• Numbers on the x-axis are continuous.

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Setting Up Histograms

• Need to determine classes
• Classes are how the data is broken into chunks
• Ex by 1s, by 10s, by 5s, etc.
• Dont want to have too many or too few
• Here are BAD histograms

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Setting Up Histograms

• Axes
• x-axis represents the classes
• y-axis represents the count for each class.
• Lets set up one
• Turn to pg 10.
• How should we set up the classes for a histogram?
• Lets make the histogram for this data.

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Setting Up Histograms(we will make the histogram
for page 10 as we go through these steps)

• Step 1 Create a table to show your classes
• Step 2 Draw axes with appropriate numbers
  marked
• Choose how the bars will be located
• Have the endpoints marked (pg. 16)
• Have the middle value marked (pg. 17)
• Step 3 Draw bars
• Step 4 Label and Title! ?

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Interpreting Histograms

• When you are asked to describe or interpret a
  histogram or any other graph, there are 4 things
  you must address.(This could also ask to describe
  the distribution.)
• This is the one class where it is ok to CUSS!!
• Lets clarify that

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Interpreting Histograms

• C Center
• State where the center of the graph is.
• Should be 50 of data on each side.
• This could be tricky on some shapes.
• U Unusual Points/Outliers
• Any point that is away from the overall pattern
  of the graph. (Eventually we will have a formula
  for this.)

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Interpreting Histograms

• S Shape
• Describe the shape of the graph.
• Here are the big ones (see sheet too)

Skewed Right
Skewed Left
Approx.Normal/ Symmetric
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Interpreting Histograms

• S Spread
• Kind of like stating the range of values.
• For now, use small, medium, or large.
• Yes that is a little subjective. Most of the
  time it will be fairly obvious.
• Now you know the proper way to CUSS!
• ?