Chapter 2 Review: Frequency Distributions and Graphical Displays of Data

Vocabulary flashcards covering key definitions, mathematical formulas, graph types, and distribution shapes from Chapter 2 Review.

Ordered array

An ordered list of data from largest to smallest or vice versa.

Distribution

A way to describe the structure of a particular data set or population.

Frequency distribution

A display of the values that occur in a data set and how often each value, or range of values, occurs.

Probability distribution

A theoretical distribution used to predict the probabilities of particular data values occurring in a population.

Ungrouped frequency distribution

A frequency distribution in which each category represents a single value.

Frequency, $f$

The number of data values in a category of a frequency distribution.

Class

A category of data in a frequency distribution.

Grouped frequency distribution

A frequency distribution in which the classes are ranges of possible values.

Class width

The difference between the lower limits or upper limits of two consecutive classes of a frequency distribution.

Lower class limit

The smallest number that can belong to a particular class.

Upper class limit

The largest number that can belong to a particular class.

Sample size, $n$

The sum of all the frequencies in a frequency distribution.

Class boundary

The value that lies halfway between the upper limit of one class and the lower limit of the next class.

Class Midpoint

Calculated as $\text{Class Midpoint} = \frac{\text{Lower Limit} + \text{Upper Limit}}{2}$.

Relative frequency

The fraction or percentage of the data set that falls into a particular class, given by $\text{Relative Frequency} = \frac{f}{n}$.

Cumulative frequency

The sum of the frequencies of a given class and all previous classes.

Pie chart

Shows how large each category of qualitative data is in relation to the whole; uses relative frequencies to divide the "pie" into wedges.

Bar graph

Bars are used to represent the amount of data in each category; one axis displays the categories of qualitative data and the other axis displays the frequencies.

Pareto chart

A bar graph with the bars in descending order of frequency; typically used with nominal data.

Side-by-side bar graph

A bar graph that compares the same categories for different groups.

Stacked bar graph

A bar graph that compares the same categories for different groups and shows category totals.

Histogram

A bar graph of a frequency distribution of quantitative data; the horizontal axis is a number line.

Frequency histogram

A histogram in which the heights of the bars represent frequencies.

Relative frequency histogram

A histogram in which the heights of the bars represent relative frequencies in either decimals or percentages.

Frequency polygon

A visual display of the frequency of each class of quantitative data that uses straight lines to connect points plotted above the class midpoints.

Ogive

A graph that displays the cumulative frequency of each class of quantitative data by using straight lines to connect points plotted above the upper class boundaries.

Stem-and-leaf plot

Retains the original data; the leaves are the last significant digit in each data value and the stems are the remaining digits.

Dot plot

Retains the original data by plotting a dot above each data value on a number line.

Line graph

Uses straight lines to connect points plotted at the value of each measurement above the time it was taken.

Time-series graph

A line graph that is used to display a variable whose values change over time.

Cross-sectional graph

Displays information collected at only one point in time.

Pictograph

A bar graph that uses pictures of objects instead of bars.

Outlier

A data value that falls outside the shape of the distribution.

Uniform graph shape

The frequency of each class is relatively the same; graph has a rectangular shape.

Symmetric graph shape

The data lie evenly on both sides of the distribution.

Skewed to the right

The majority of the data fall on the left side of the distribution.

Skewed to the left

The majority of the data fall on the right side of the distribution.