Graphing Notes

Different Types of Graphs Tables, charts and graphs are convenient ways to clearly show your data.

All Graphs must have proper labels!

All graphs must include all labels X axis is your Manipulated (independent) variable Y axis is your Responding (dependent) variable

The cafeteria wanted to collect data on how much milk was sold in 1 week. The table below shows the results. We are going to take this data and display it in 2 different types of graphs.

There are three basic graph forms. Notice how each of the following examples are used to illustrate the data. Choose the best graph form to express your results.

Bar Graph A bar graph is used to show relationships between groups. The two items being compared do not need to affect each other. It's a fast way to show big differences. Notice how easy it is to read a bar graph.

Line Graph A line graph is used to show continuing data; how one thing is affected by another. It's clear to see how things are going by the rises and falls a line graph shows. DRY MIX Or ROTATE your DATA TABLE.

Scale notes for line graphs Choose the right scale for the axis – Must be consistent (same spacing) – Must include all data – Zero isn’t always data! – Choose increments that make it easy to read and place numbers. If my data is.1 through.3 I don’t want to count by 10’s!

Bar Graph Line Graph The same data displayed in 2 different types of graphs.

On what day did they sell the most chocolate milk? a. Tuesday b. Friday c. WednesdayTuesdayb. Friday Wednesday

On what day did they sell the most chocolate milk? a. Tuesday b. Friday c. WednesdayTuesdayb. Friday Wednesday

On what day did they have a drop in chocolate milk sales? a. Thursday b. Tuesday c. MondayThursdayTuesdayMonday

On what day did they have a drop in chocolate milk sales? a. Thursday b. Tuesday c. MondayThursdayTuesdayMonday

Choosing the Right Graph Use a bar graph if you are not looking for trends (or patterns) over time; and the items (or categories) are not parts of a whole. Use a pie chart if you need to compare different parts of a whole, there is no time involved and there are not too many items (or categories). Use a line graph if you need to see how a quantity has changed over time. Line graphs enable us to find trends (or patterns) over time.

To go from a data table to a graph D ependent R esponding Y - axis M anipulated I ndependent X - axis OR Remember DRY MIX

Take your data table

Rotate it 90⁰ Left

And the bottom tells you the X label; the side, Y label Graph X Graph Y

What is correlation? Correlation is a statistical procedure that is used in a wide variety of settings Correlation is often used to express the relationship between two variables...

Age and height of children Number of days students are absent and their level of achievement Scores on two different student assessments, such as reading and math Earlier versus later scores, such as earlier and later performance in writing For instance, correlation might be used to express the relationship between… What is correlation?

Direct Relationships (aka Direct Correlation, Positive Correlation, Positive Relationship) When values on two variables tend to go in the same direction, we call this a direct relationship. Draw the line

Direct Relationships (aka Direct Correlation, Positive Correlation, Positive Relationship) The correlation between children’s ages and heights is a direct relationship. That is, older children tend to be taller than younger children. This is a direct relationship because children with higher ages tend to have higher heights.

Direct Relationship That is, older children tend to be taller than younger children. This is a direct relationship because children with higher ages tend to have higher heights. To write this as a relationship, if X goes up, Y goes up.

Inverse Relationships (AKA Inverse Correlation, Negative Correlation, Negative Relation) When values on two variables tend to go in opposite directions, we call this an inverse relationship. Draw the line

Inverse Relationships (AKA Inverse Correlation, Negative Correlation, Negative Relation) The correlation between students’ number of absences and level of achievement is an inverse relationship. That is, students who are absent more often tend to have lower achievement. This is an inverse relationship because children with higher numbers of absences tend to have lower achievement scores.

Inverse Relationship That is, students who are absent more often tend to have lower achievement. This is an inverse relationship because children with higher numbers of absences tend to have lower achievement scores. To write this as a relationship, if X goes up, Y goes down (or vice-versa).

What kind of relationship? Direct Inverse

What kind of relationship? Direct Inverse

What kind of relationship? Direct Inverse

What kind of relationship? Direct Inverse

Is there a relationship?

NO!

No Correlation: Data is in a random pattern. There is no relationship or cause and effect between variables. Draw the dots