Term
| Numerical Variable (Quantitative Variable) |
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Definition
| Represents the most common type of variable. The data gathered about these variable will always be a number. |
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Term
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Definition
| Categorical variables are variables that place people or things into categories, such as male or female, color, size, etc. Categorical variables can be organized in bar graphs or two-way tables to show their distributions or frequencies. |
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Term
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Definition
| This is a table that will display two different variables and how they relate to one another. |
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Term
| Two-way Relative Frequency for Whole Table |
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Definition
| Two-way relative frequency tables show percentages in each cell. To find the percentages, divide the number in each cell by the table total. |
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Term
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Definition
| Marginal distribution, or marginal frequencies, is the total of a column divided by the table total or the total of a row divided by the table total. This calculation gives us a percentage that tells us the "percent of data". |
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Term
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Definition
| We use conditional distributions, or conditional frequencies, when we are only interested in a subpopulation, or you may want to think of this as looking at a sub-category. In conditional distributions we put "conditions" on what we are interested at analyzing and look at every entry in that particular row or every entry in that particular column. This is easiest to do with the help of our table. Comparing in this way allows us to describe the associations between the row and the column variables. |
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Term
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Definition
| This variable can take on infinitely many values and can be any number between any other two number. (there is no break in the data) |
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Term
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Definition
| These variables take on distinct and a finite number of values. |
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Term
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Definition
| The number of times that each value occurs in a set of data. |
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Term
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Definition
| A time series graph is a graph that displays time on the horizontal axis (x-axis) and the variable of interest on the vertical axis (y-axis). A time series graph is used to show the change in a variable over time. |
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Term
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Definition
| A bar chart is used for displaying and analyzing categorical data. The horizontal axis displays the various categories and the vertical axis displays the frequency in each category. The frequency is a measure of how often a data value occurs. A bar is drawn to show the frequency for each category. |
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Term
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Definition
| A segmented bar chart displays partitioned bars for each variable. The size of partitions allows for comparisons between each of the variables. |
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Term
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Definition
| A histogram is used to display large sets of data. Because the data represents a continuous numeric variable, the bars of the histogram are used to divide the data into class intervals or bins. The horizontal axis displays the variable of interest and the vertical axis displays the frequency of the data in each interval. In statistics histograms are most often used for analyzing large amounts of data. |
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Term
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Definition
| A circle graph, better known as a pie chart, shows the percentage of observations for each category. These graphs are best used when you want to compare one or more categorical variables. |
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Term
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Definition
| A dot plot is a graph used to display every value of a variable. Each data value is shown as a dot placed above a horizontal line. Dot plots are used for small data sets. Dot plots allow us to easily summarize the data and see the range of data values. |
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Term
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Definition
| A stem plot is a graph that displays numeric data often separated by a vetical line. The left side of the line is called the stem and the right side is called the leaf. Some stemplots are designed to show two sets of data. |
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Term
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Definition
| An ogive is a graph of cumulative frequencies for a set of data. These graphs are used to calculate how many data values lie above or below a specific data value. These graphs are best used to display cumulative sums of the data. A steeper slope from one data point to another data point indicates a greater increase in the frequency of the data values |
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