Graphs Ok, let’s apply this information to graphs. We’re going to talk about 3 different types of graphs… Ok, let’s apply this information to graphs. We’re going to talk about 3 different types of graphs… Line graphsLine graphs Bar graphsBar graphs Pie charts or Circle graphsPie charts or Circle graphs

Graphs What are some subjects that you might find graphs being used? What are some subjects that you might find graphs being used? What kind of graphs have you seen before? What kind of graphs have you seen before?

Line Graphs Line graphs are used to show trends. Line graphs are used to show trends. A trend is the general direction that something moves A trend is the general direction that something moves Line graphs usually show how something changes over time. Line graphs usually show how something changes over time.

Line Graphs So, you might find line graphs describing how… So, you might find line graphs describing how… Car sales increase or decrease over timeCar sales increase or decrease over time How the stock market goes up or downHow the stock market goes up or down

How much the population increases each yearHow much the population increases each year

Line Graph So… how are these graphs set up? So… how are these graphs set up? Line graphs have a horizontal axis and a vertical axis. Line graphs have a horizontal axis and a vertical axis.

Line Graphs The horizontal axis goes across the bottom of the graph… think of the horizon…The horizontal axis goes across the bottom of the graph… think of the horizon… The vertical axis runs up and down along the side of the graphThe vertical axis runs up and down along the side of the graph

Line Graph The independent variable is labeled on the horizontal axis. The independent variable is labeled on the horizontal axis. The dependent variable is labeled on the vertical axis. The dependent variable is labeled on the vertical axis.

Which axis? So, if we used a line graph to describe how the population increases each year… So, if we used a line graph to describe how the population increases each year… What axis would the year be on? What axis would the year be on? The X- axis!

Labeling the Axis Both axis should be numbered in even intervals. Both axis should be numbered in even intervals. This means they should have even spacing of numbers along the axis. This means they should have even spacing of numbers along the axis

Ordered pairs from a data table are plotted on the graph and a line is drawn to connect the data points. Ordered pairs from a data table are plotted on the graph and a line is drawn to connect the data points. The line shows a trend or relationship between the two variables. The line shows a trend or relationship between the two variables.

Bar Graphs Now let’s talk about Bar Graphs… Now let’s talk about Bar Graphs…

Bar Graphs Bar graphs are used to show differences between events or individuals. Bar graphs are used to show differences between events or individuals. Bar graphs are useful for comparing information collected by counting. Bar graphs are useful for comparing information collected by counting.

Bar Graphs For instance, a bar graph could be used to compare how many baskets were made by 5 different people in a free-throw competition. For instance, a bar graph could be used to compare how many baskets were made by 5 different people in a free-throw competition. Or, a bar graph could be used to compare the populations of several different cities. Or, a bar graph could be used to compare the populations of several different cities.

Bar Graphs Each bar in a bar graph represents a number counted at a particular time… Each bar in a bar graph represents a number counted at a particular time… This would include the number of free-throws each person shoots… This would include the number of free-throws each person shoots… Or, the population of the cities being compared. Or, the population of the cities being compared.

Bar Graphs Similar to the line graph, the independent variable is labeled along the horizontal axis. Similar to the line graph, the independent variable is labeled along the horizontal axis. The dependent variable is labeled along the vertical axis. The dependent variable is labeled along the vertical axis.

Free Throw Example In our example of the free-throw comparison, which variable would be independent? In our example of the free-throw comparison, which variable would be independent? Which would be the dependent variable? Which would be the dependent variable?

Free Throws Example Remember… we are comparing how many free-throws (or baskets) are made by each person. Remember… we are comparing how many free-throws (or baskets) are made by each person. Which variable “stands alone” and which “relies” on another variable? Which variable “stands alone” and which “relies” on another variable?

Free Throw Example The number of free throws (or baskets) that are made relies on which person threw the ball. The number of free throws (or baskets) that are made relies on which person threw the ball. So, the number of free throws would be our dependent variable. So, the number of free throws would be our dependent variable.

Free Throw Example The person throwing the ball is the independent variable. The person throwing the ball is the independent variable.

Free-Throw Example Then, how would the axis be labeled for the free-throw example? Remember, the independent variable is labeled on the horizontal axis… Then, how would the axis be labeled for the free-throw example? Remember, the independent variable is labeled on the horizontal axis…

Free-Throw Example The independent variable (the person) would be labeled along the horizontal (x) axis. The independent variable (the person) would be labeled along the horizontal (x) axis. The dependent variable (number of free-throws made) would be labeled along the vertical (y) axis. The dependent variable (number of free-throws made) would be labeled along the vertical (y) axis.

Pie Graph Pie graphs show different parts of a whole amount. Pie graphs show different parts of a whole amount. Pie graphs can be used for showing… Pie graphs can be used for showing… Types of cars sold in the USTypes of cars sold in the US How memory is used on a hard driveHow memory is used on a hard drive What are some other comparisons that you could use a pie graph for? What are some other comparisons that you could use a pie graph for?

Pie Graphs A pie graph starts with a circle. A pie graph starts with a circle. This represents the total amount you are looking at. This represents the total amount you are looking at.

Pie Graph The pie is then divided into different sized slices to represent different parts of the total amount. The pie is then divided into different sized slices to represent different parts of the total amount.

Pizza!! Think of a pizza!! Think of a pizza!! Let’s say you ordered a pizza with different sized slices and different toppings on each. Let’s say you ordered a pizza with different sized slices and different toppings on each.

Each slice represents something different because of the different topping… but… Each slice represents something different because of the different topping… but… Each slice is still a part of the same pizza. Each slice is still a part of the same pizza. They are just different parts of the whole pizza. They are just different parts of the whole pizza.

Pizza!! The size of each slice determines what fraction of the whole pizza the slice is. The size of each slice determines what fraction of the whole pizza the slice is. If a slice was took up half of the whole pizza, it would be ½ the whole pizza. If a slice was took up half of the whole pizza, it would be ½ the whole pizza. This can also be considered 50% of the whole pizza. This can also be considered 50% of the whole pizza.

Pie graphs are very similar… Pie graphs are very similar… Each slice of the circle represents a part of a whole amount. Each slice of the circle represents a part of a whole amount.

Cars For instance, a pie graph might look at the color of 100 cars. For instance, a pie graph might look at the color of 100 cars. Of those 100 cars… Of those 100 cars… 25 might be red25 might be red 25 might be blue25 might be blue 50 might be white50 might be white

Cars So… there are 25 red cars of the total 100 cars. So… there are 25 red cars of the total 100 cars. If the circle represents the whole 100 cars, what size would the slice be for the red cars? If the circle represents the whole 100 cars, what size would the slice be for the red cars? It would be 25/100 which is ¼ or 25% of the whole circle. It would be 25/100 which is ¼ or 25% of the whole circle.

Cars Similarly, ¼ or 25% of the whole circle would represent the blue cars… and… Similarly, ¼ or 25% of the whole circle would represent the blue cars… and… ½ or 50% of the whole pie graph would represent white cars. ½ or 50% of the whole pie graph would represent white cars.

The fraction is equal to the number of white cars divided by the total number of cars. The fraction is equal to the number of white cars divided by the total number of cars. So the fraction would be the desired amount divided by the total amount. So the fraction would be the desired amount divided by the total amount. The fraction would be The fraction would be