chapter 2 unit b E280

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frequency distribution (table) for qualitative data
- groups the data into categories and records how many observations fall into each category
- this can be done Nominal or Ordinal scale data
A frequency distribution (a table that show frequency of accuracy) for quantitative data
- groups the data into numerical intervals called classes , and records the number of observations that fall into each class
- either Interval or Ratio scale
guidelines when constructing frequency distribution (Quantitative data)
Approximating the class width
- Classes are Mutually Exclusive (cannot overlap)
- Classes are Exhaustive (cannot miss a value)
- Largest value-Smallest value
- Number of classes
Cumulative frequency distribution

specifies how many observations fall below the upper limit of a particular class
relative frequency distribution
identifies the proportion or fraction of values that fall into each class
- CRF=Class freq
- total number of observation
histogram

is a visual representation of frequency or a relative frequency distribution
the shape of most data distributions may be categorized as either
- Symmetric- a mirror image, same on both side
- skewed- (positively skewed right) (negatively skewed left)
ogive

plot the cumulative frequ of each class above the upper limit of the corresponding class
polygon

plot the class midpoints on x axis and associated frequency in y axis
Steam and leaf diagram
- visual display of quantitative (numerical) data it gives an overall picture of the data's center and variability data
- set is separated into two parts; the stem consists of the leftmost
- digit, while the leaf is the last digit that is relevant for data
- distinction
scatterplot
- is uesed to determine if two variables are related
- each point is pairing
- Linear- as indicated by an upward or downward sloping trend
- Curvilinear-
- no relationship-

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Cshowalter

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chapter 2 unit b E280

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Updated

2015-05-30T18:31:10Z

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