Glossary page F
Features (of distributions)
Distinctive parts of distributions that usually become apparent when the distribution is presented in a data display. The parts worthy of comment will depend on the type of display and how clearly the part stands out.
Curriculum achievement objectives references
Statistical investigation: Levels (2), (3), (4), (5), 6, (7), (8)
Statistical literacy: Levels 2, (3), (4), (5), (6), (7), (8)
Fivenumber summary
Five numbers that form a summary for the distribution of a numerical variable. The five numbers are minimum value, lower quartile, median, upper quartile, and maximum value. Together they convey a lot of information about the features of the distribution.
Example
The fivenumber summary for the weights of the 302 male students who answered an online questionnaire given to students enrolled in an introductory statistics course at the University of Auckland is 51 kg, 65 kg, 72 kg, 81 kg, 140 kg.
Curriculum achievement objectives references
Statistical investigation: Levels (5), (6), (7), (8)
Forecast
An assessment of the value of a variable at some future point of time, often based on an analysis of timeseries data.
See: estimate, prediction
Curriculum achievement objectives reference
Statistical investigation: Level (8)
Frequency
For a wholenumber variable in a data set, the number of times a value occurs.
For a measurement variable in a data set, the number of occurrences in a class interval.
For a category variable in a data set, the number of occurrences in a category.
See: relative frequency, tally chart
Curriculum achievement objectives references
Statistical investigation: Levels (4), (5), (6), (7), (8)
Frequency distribution
The variation in the values of a variable in which the method of displaying this variation uses frequencies.
For wholenumber data, a frequency distribution may be displayed as a set of values and their corresponding frequencies in table form (frequency table) or on an appropriate graph.
For measurement data, a frequency distribution may be displayed as a set of intervals of values (class intervals) and their corresponding frequencies in table form (frequency table) or on an appropriate graph.
For category data, a frequency distribution may be displayed as a set of categories and their corresponding frequencies, in table form (frequency table) or on an appropriate graph.
See: distribution, experimental distribution, frequency table, sample distribution
Curriculum achievement objectives references
Statistical investigation: Levels (4), (5), (6), (7), (8)
Probability: Levels (4), (5), (6), (7), (8)
Frequency table
Any table that displays the frequencies of values of one or more variables in a data set.
For a wholenumber variable in a data set, a table showing each value of the variable and its corresponding frequency.
For a measurement variable in a data set, a table showing a set of class intervals for the variable and the corresponding frequency for each interval.
For a category variable in a data set, a table showing each category of the variable and its corresponding frequency.
A frequency table will often have an extra column that shows the percentages that fall in each value, class interval, or category.
See: oneway table, twoway table
Example
The number of days in a week that rain fell in Grey Lynn, Auckland, from Monday 2 January 2006 to Sunday 31 December 2006 is recorded in the frequency table below.
Count of weeks by number of days with rain
0
 2

1
 5

2
 5

3
 5

4
 19

5
 6

6
 6

7
 4

Total
 52

A frequency table with more information is shown below.
Count of weeks by number of days with rain, with percentages
0
 2
 3.8%
 3.8%

1
 5
 9.6%
 13.5%

2
 5
 9.6%
 23.1%

3
 5
 9.6%
 32.7%

4
 19
 36.5%
 69.2%

5
 6
 11.5%
 80.8%

6
 6
 11.5%
 92.3%

7
 4
 7.7%
 100.0%

Total
 52



Curriculum achievement objectives references
Statistical investigation: Levels (3), (4), (5), (6), (7), (8)
Probability: Levels (3), (4), (5), (6)
Last updated September 27, 2013
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