AP Statistics Curriculum 2007 EDA Freq
General Advance-Placement (AP) Statistics Curriculum - Summarizing data with Frequency Tables
Summarizing data with Frequency Tables & Histograms
There are two ways to describe a data set (sample from a population) - Pictorial Graphs or Tables of Numbers. Both are important for analyzing data.
- A frequency distribution is a display of the number (frequency) of occurrences of each value in a data set.
- A relative frequency distribution is a display of the percent (ratio or frequency to sample-size) of occurrences of each value in a data set.
- A percentile is the value of a variable that divides the real line into two segments - the left one containing certain percent (say 13%) of the observations for the specific process, and the right interval containing the complementary percentage of observations (in this case 87%). The 30th percentile is the value (measurement) bound above 30% and below 70% of the observations from a process.
- The (three) quartiles are the special cases of percentiles for Q1=25%, Q2=50% (median) and Q3=75%.
The table below shows the stage of disease at diagnosis of breast cancer in a random sample of 2092 US women.
Computational Resources: Internet-based SOCR Tools
- SOCR Charts allows you to generate graphical representations (including frequency histograms) of a variety of datasets.
- The SOCR Charts activities provide usage-instructions, examples and demonstrations of how to use SOCR Charts.
You can copy and paste the first 2 columns in the data table above in the SOCR Charts (BarChart --> XYPlot --> HistogramDemo7). You can see this SOCR Charts activity for help with histogram plots.
- The graph below illustrates the (raw) frequency histogram (using counts)
- The graph below show the relative frequency histogram (using the last column of the table above).
- SOCR Home page: http://www.socr.ucla.edu
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