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25 Cards in this Set
- Front
- Back
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Two things data determine
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1. Graphs
2. Summaries |
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Categorical Data
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Graphs: bar graphs, pie charts
Summaries: counts or percentages |
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Quantitative Data
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Graphs: dotplot,stemplot,histograms, boxplots
Summaries: mean,median,quartiles, standard deviation |
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Bar graphs vs pie charts
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Bar graphs are better as comparing bars is easier to comparing wedges in pie chart
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Dotplot procedure
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1. Over a number line put a dot on the value provided
2. Put an additional dot on a repeated value and stack in on top of a prior noted dot/value. |
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Stemplot procedure
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1. Determine stems and leaves
2. Arrange stems on left and leaves on right |
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Further on stemplots
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1. stems (tens place)
2. leaves (ones place) 3. We can divide stems into two lines 4. on two line stems 0-4 leaves are on the first line and 5-9 are on the second line. |
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Leaf Unit (LU)
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***LU of 1 means that stems=tens & leaves=units
***LU of 10 means that stems=hundred & leaves=tens |
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Two things data determine
|
1. Graphs
2. Summaries |
|
|
Categorical Data
|
Graphs: bar graphs, pie charts
Summaries: counts or percentages |
|
|
Quantitative Data
|
Graphs: dotplot,stemplot,histograms, boxplots
Summaries: mean,median,quartiles, standard deviation |
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Bar graphs vs pie charts
|
Bar graphs are better as comparing bars is easier to comparing wedges in pie chart
|
|
|
Dotplot procedure
|
1. Over a number line put a dot on the value provided
2. Put an additional dot on a repeated value and stack in on top of a prior noted dot/value. |
|
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Stemplot procedure
|
1. Determine stems and leaves
2. Arrange stems on left and leaves on right |
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Further on stemplots
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1. stems (tens place)
2. leaves (ones place) 3. We can divide stems into two lines 4. on two line stems 0-4 leaves are on the first line and 5-9 are on the second line. |
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Leaf Unit (LU)
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***LU of 1 means that stems=tens & leaves=units
***LU of 10 means that stems=hundred & leaves=tens |
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historams
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1. Choose the interval width and starting point for first inerval
2. Count number of observations in each interval 3. Display no.of observations in each interval with a vertical bar. |
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more on histograms
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histograms are not unique as you can change them by:
1.changing width of interval(more values of x axis are included as a larger interval value, see applet) 2.changing starting point |
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comparing dotplots, stemplots and histograms
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1.dotplots and stemplots for SMALL data sets
2. histograms for LARGE data sets. 3. stemplots help in identifying outliers as they are like histograms. 4. stemplot vs dot plot is personal preference. 5. histograms usu require computers |
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Shape
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*it is the general pattern of distribution
look for: symmetery vs skewness & tails vs peaks e.g bell shaped, left and right skewed, bimodal (two peaks),flat |
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Center
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*midpoint on x axis
look for: half data above and half data below |
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spread
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*variablilty of data in a distribution
look for: min and max |
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outliers
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*fall outside overall pattern of distribution.
note: a small break in a histogram may not mean that there is an outlier. |
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Bar Charts v Histograms
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*(These are properties of bar charts)
1. Horizontal axis is categorical 2.spread,center and shape have no meaning 3. bars have breaks |
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Histograms v Bar Charts
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*(These are properties of histograms)
1. x axis is quantitative 2. described by spread, shape and center 3. bars are adjacent |
