Ch 11 Stats

Pictogram

A graphic technique in which pictures are used in the display of data. An attractive alternative to a bar graph in that it uses pictures to show the frequency of data.

Categorical data

Four types of data (nominal, ordinal, interval, and ratio) that represent values or observations that can be sorted into a category; also called scales of measurement.

What are the 4 scales of measurement of categorical data?

Nominal Ordinal Ratio Interval

Numerical data

there are two types of numerical data- discrete and continuous.

when creating graphs, following these general guidelines:

1. title must relate to what the graph is displaying 2. when several variables are included on the graph, each should be identified by using a legend. 3. categories should be natural- the vertical axis should always start with zero. the scale of the values for the x axis reads from the lowest value on the left to highest on the right. 4. scale captions are placed on both axes to identify the values clearly. 5. graphs should emphasize the horizontal. 6. the exact reference to an outside source should be given.

Pie chart/ Pie graph

A graphic technique in which the proportions of a category are displayed as portions of a circle. -Method of displaying data as a component parts of a whole. use a pie chart when you want to show each category's percentage of the total.

Table

An organized arrangement of data, usually in columns and rows.

Scales of measurement

See categorical data

data display-tables

an orderly arrangement of values that groups data into rows and columns. almost any type of quantitative information can be grouped into tables.

frequency distribution tables

shows the values that a variable can take and the number of observations associated with each value. a variable is a characteristic or property that may take on different values.

Scatter diagram

A graph that visually displays the linear relationships among factors. Used to graphically show the relationships between two numerical variables. a scattergram is used to determine whether there is a correlation or relationship between two characteristics.

Run chart

A type of graph that shows data points collected over time and identifies emerging trends or patterns.

advantages to using tables

more info can be presented exact values can be read to retain precision supportive details can be provided less work and fewer costs are required flexibility is maintained without distortion of data

Bar chart/ Bar graph

A graphic technique used to display frequency distributions of nominal or ordinal data that fall into categories; also called bar graph. -Shows categories best Appropriate for displaying categorical data. the various categories of observation are presented along a horizontal axis or x-axis. the vertical axis or y axis, displays the frequency of the data. data representing frequencies, proportions or percentages of categories are often displayed using bar graphs.

Histogram

A graphic technique used to display the frequency distribution of continuous data (interval or ratio data) as either numbers or percentages in a series of bars. Used to display frequency distributions for continuous numerical data. they're created from frequency distribution tables.

Line graph

A graphic technique used to illustrate of all the knowledge available about a topic from sources such as books, journal articles, theses, and dissertations. Used to show data over time (days, weeks, months). The x-axis shows the time period and the y axis shows the values and the variable.

Interval data

A type of data that represents observations that can be measured on an evenly distributed scale beginning at a point other than true zero. No ZERO POINT an example is temperature in fahrenheit. the intervals between variables are equal. an example is time. there are 24 hours in a day and the difference between each hour is the same. there is no zero value.

Ordinal data

A type of data that represents values and observations that can be ranked or ordered. "to put something in order" On the ordinal scale, only the order of the numbers is meaningful, not the numbers themselves. this is because the intervals or distances between categories are not necessarily equal. Example, head injuries may be classified according to level of severity...where 4 is fatal, 3 is severe, 2 moderate and 1 minor.

Nominal data

A type of data that represents values or observations that can be labeled or named and where the values fall into unordered categories; also called dichotomous data. Lowest level of measurement Observations are organized into categories in which there is no recognition of order: Ex: true/false, male/female, types of insurance carriers or patient occupations.

Frequency polygon

A type of line graph that represents a frequency distribution. similar to a histogram in that it is a graph depicting the frequency of continuous data. however, a frequency polygon is in line form instead of bar form.

Ratio data

Data that may be displayed by units of equal size and placed on a scale starting with zero and thus can be manipulated mathematically. The highest level of measurement There is a defined unit of measure A real zero point Intervals between vales are equal. an example is age. the difference between 1 and 2 is the same. there is a zero point.

Continuous data

Data that represent measurable quantities but are not restricted to certain specified values. A variable that is continuous can take on a fractional value. for example, a patient's temp may be 102.5. another example is height. age is another. the only limiting factor for a continuous observation is the degree of accuracy with which it can be measured. MEASUREMENT ON THE INTERVAL AND RATIO SCALES CAN BE GROUPED- INTERVAL AND RATIONS ARE CONTINUOUS.

Discrete data

Data that represent separate and distinct values or observations; that is, data that contain only finite numbers and have only specified values. Finite numbers are whole numbers They can have only specified values. For example, the number of children in a family- there can only be 2-3, not 2.25. another example could be the number of motor vehicle accidents in a community or the number of times a woman has given birth, the number of new cases of cancer within your state in the past five years. FOR THE MOST PART, MEASUREMENTS ON THE NOMINAL AND ORDINAL SCALES ARE DISCRETE.

graphs

graphs of various types are the best means fro presenting data for quick visualization of relationships.