Te Kete Ipurangi
Communities
Schools

# Glossary page F

A  B  C  D  E  F G  H  I J K  L  M  N  O  P  Q  R  S  T  U  V  W X Y Z

## 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)

## Five-number 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 five-number 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 time-series data.

See: estimate, prediction

### Curriculum achievement objectives reference

Statistical investigation: Level (8)

## Frequency

For a whole-number 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 whole-number 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: distributionexperimental 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 whole-number 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: one-way table, two-way 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.

 Number of days with rain Number of weeks 0 2 1 5 2 5 3 5 4 19 5 6 6 6 7 4 Total 52