Data Analysis
Stem and Leaf Plots
Definition: A diagram that quickly summarizes data while maintaining the individual data points
Double Stem and Leaf Plots are used when comparing two different sets of data.
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Measures of Central Tendency
Any of a number of ways of specifying a "central value".
Mean: Add all the numbers in a set, then divide by how many are in the set.
Median: Arrange the list of numbers in order from least to greatest, then find the middle number (or average of the 2 middle numbers if it is even).
Mode: In a set of numbers, the number that occurs most often.
Range: Subtract the smallest number in the set from the largest number in the set.
Pictographs
Pictograms are graphs using pictures to represent their numerical values.
Every Pictograph has clear title and values represented.
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Line Graph
A line graph shows trends over time.
Horizontal Line = Time
Vertical Line = Variable
Trend Line - Line that closely fits the data and is used to describe it.
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Bar Graphs
Definition: Has space between the bars and is used to depict categorial data. Order does not matter.
There are other bar graphs such as percentage bar graphs, double bar graphs, and stacked bar graphs.
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Histograms
Histograms must have an order, and are made up of adjoining rectangles or bars. Histograms can be made easily with the use of a single-sided stem and leaf plot.
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Pie Charts
Is a circular chart divided into sectors, illustrating numerical proportion.
Pie charts are very widely used in the business world and the mass media.
Central angle - to find the percent of circle time 360 degrees
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Dot Plots
Dot Plots contain Numerical Data on a number line
Outlier - Greater or lesser than
Cluster - Isolated group of points
Gap - Large Space
Mode - number Occurs the most often on the line plot
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