Chapter 2: Organizing and Summarizing Data

Vocabulary practice flashcards covering qualitative and quantitative data organization, tables, graphs, distribution shapes, and display methods from Chapter 2 of Sullivan's Statistics.

Raw data

Data collected from a survey or designed experiment that has not yet been organized into a manageable form.

Frequency distribution

A tabular display that lists each category of data and the number of occurrences (frequency) for each category.

Relative frequency

The proportion or percent of observations within a category, calculated using the formula: $\text{relative frequency} = \frac{\text{frequency}}{\text{sum of all frequencies}}$.

Relative frequency distribution

A table that lists each category of data alongside its corresponding relative frequency.

Bar graph

A chart constructed by labeling categories of data on one axis and frequency or relative frequency on the other, using rectangles of equal width whose heights represent each category's value.

Pareto chart

A bar graph in which the categories are arranged and drawn in decreasing order of frequency or relative frequency.

Pie chart

A circular display divided into sectors where each sector represents a category, and the area of each sector is proportional to the frequency of that category.

Histogram

A graphical display for quantitative data consisting of adjacent rectangles of equal width that touch each other, where each rectangle's height corresponds to the frequency or relative frequency of the class.

Classes

Categories or intervals of numbers into which quantitative data are grouped.

Lower class limit

The smallest data value that can belong to a particular class.

Upper class limit

The largest data value that can belong to a particular class.

Class width

The difference between consecutive lower class limits in a frequency distribution.

Stem-and-leaf plot

A graphical display of quantitative data where each value is split into a stem (the digits to the left of the rightmost digit) and a leaf (the rightmost digit).

Split stem

A technique in a stem-and-leaf plot where stem values are repeated to spread out bunched data and reveal distribution patterns more clearly.

Dot plot

A statistical graph drawn by placing each observation along a horizontal axis in increasing order and placing a dot above the observation each time it occurs.

Uniform distribution

A distribution shape in which the frequency of each value of the variable is evenly spread out across the values.

Bell-shaped distribution

A symmetric distribution shape where the highest frequency occurs in the middle and frequencies tail off to both the left and right.

Skewed right

A distribution shape where the tail to the right of the peak is longer than the tail to the left of the peak.

Skewed left

A distribution shape where the tail to the left of the peak is longer than the tail to the right of the peak.

Class midpoint

The sum of consecutive lower class limits divided by $2$.

Frequency polygon

A graph that uses points connected by line segments to represent class frequencies, plotted above each class midpoint at a height equal to the class frequency, with ends connecting to the horizontal axis.

Cumulative frequency distribution

A table displaying aggregate counts, showing the total number of observations less than or equal to a category (discrete data) or less than or equal to the upper class limit (continuous data).

Cumulative relative frequency distribution

A table displaying the proportion or percentage of observations less than or equal to a category (discrete data) or less than or equal to the upper class limit (continuous data).

Ogive

A graph representing cumulative frequency or cumulative relative frequency, constructed by connecting points plotted at upper class limits and anchored to the horizontal axis at the upper limit preceding the first class.

Time series data

Quantitative values of a variable measured at different points in time.

Time-series plot

A graph obtained by plotting the time of measurement on the horizontal axis and the variable's corresponding value on the vertical axis, connecting consecutive points with line segments.