Ways of Looking at Groups of Numbers Business Communications & Publications

Groups of Numbers When large groups of numbers are gathered, 3 types of simple analyses help to reveal certain facts or trends about the group: Figuring the mean (the average) Finding the median (the midpoint) Looking at the mode (the most common number)

The Mean Mean: simply the average The mean test score for a given group is obtained by adding all of the scores & dividing the total number of scores What is the mean for each of the following groups of numbers? Group X: 6, 6, 7, 9, 2, 8, 1, 5, 6 Group Y: 54, 66, 71, 73, 84, 87, 88, 91

The Median The median is the midpoint To find the median, you simply arrange the scores in numerical order. Then you count down to the exact middle of the list Identify the median in each of the following sets of numbers: 1, 2, 3, 4, 5 0, 1, 2, 2, 5, 55, 90, 98, 98 96, 88, 86, 80, 76, 74, 72

The Mode The mode is defined as the most common number – the one that occurs most frequently What is the most common number in this list? 1, 2, 2, 2, 3, 4, 5, 5 Fact: Every group of numbers has a mean and a median. Not every group has a mode

Using Numbers When No Quantity is Involved Numerals can also be used in: performance ratings Examples: class grade, gymnastics score Subjective ratings Clusters of information obtained about how people feel or think

Using Tables, Charts, & Graphs They are organized, attention-getting ways to present information Clear, easy-to-read ways of summarizing data

Tables Contain organized lists of information, arranged in columns & rows The number of columns you use is dictated by the information & how it can best be arranged Each column is given a heading that describes the data in it Most important column: one that is designed to be the comparison point or focal point for the reader (chronological, alphabetical, numeric)

Pie Charts Also known as circle graphs, get their name because they look like pies cut into slides Pie charts start with a circle The circle represents 100% of something – the whole thing The slices represent the parts of the whole They are used to illustrate, persuade, or compare

Line Graphs Line graphs turn numbers into drawings The use of a line graph helps make the numbers more meaningful to the reader because it makes a visual comparison between two kinds of change In business, a line graph often shows change in dollars earned from month to month or from year to year, so the comparison is between money and time. Both increases & decreases can be illustrated well with a line graph

Bar Graphs Usually compare 2 or more things to time or space The bars may be either vertical or horizontal A different-colored bar is used for each of the years for easier visual comparison