1. Warm-up
Write and respond: How should you write your hypothesis?

2. Graphing

3. Graph
A diagram showing the relation between variable quantities, typically of two variables, each measured along one of a pair of axes at right angles.

4. Types
Line graph Bar graph Pie chart Scatter Plots

5. Line Graph
good at showing specific values of data, meaning that given one variable the other can easily be determined.
show trends in data clearly, meaning that they visibly show how one variable is affected by the other as it increases or decreases.
enable the viewer to make predictions about the results of data not yet recorded.
Variables:
Independent on the x-axis
Dependent on the y-axis

6. Problems
Not using consistent scales on axes Comparing graphs with 2 different scales
1. What was the minimum wage in January, 1978?
2. When did the minimum wage reach $3.35?
3. Between what time periods was the largest increase in minimum wage?
4. Based on your observations of the graph, make a prediction about what the wage might be in the year 2000.
5. What about the scales used on the graph might make the data appear differently than how it really is?

7. Bar Graph display data in a similar way to line graphs
uses a horizontal or vertical rectangular bar that levels off at the appropriate level
rather than using a point on a plane to define a value

8. Usefulness
They make comparisons between different variables very easy to see. They clearly show trends in data, meaning that they show how one variable is affected as the other rises or falls. Given one variable, the value of the other can be easily determined.

9. Reading Bar Graphs
1. What was the most popular career chosen by middle school students? 2. What was the least popular career chosen by middle school students? 3. Which career was chosen by 103 students? 4. List the careers chosen by the middle school students from most to least popular. 5. Which career was chosen by 89 students?

10. Pie Charts AKA Circle graphs Don't use a set of axes to plot points
Display percentages
Used to compare different parts of the same whole
Problems:
Leaving out one or more of the parts of the whole.
Not defining what the whole stands for.

11. Expenditures for State and Local Governments
Reading Pie Charts
What type of information is being presented on this graph? If the total spending is $50,000, how much money was spent on highways? Approximately how many times the amount of spending on highways is spent on education? Approximately what fraction of the total expenditures are spent on highways and public welfare combined?
Expenditures for State and Local Governments

12. Scatter Plots Similar to line graphs
use horizontal and vertical axes to plot data points.
Usually consist of a large body of data
Have a very specific purpose
Scatter plots show how much one variable is affected by another.
The relationship between two variables is called their correlation
The closer the data points come when plotted to making a straight line, the higher the correlation
Strength of relationship

13. Perfect Correlation
Positive Correlation
Negative Correlation
a straight line going from the origin out to high x- and y- values Value of 1
line goes from a high-value on the y-axis down to a high-value on the x-axis Value of -1

14. Imperfect Correlations
Which graph would have a correlation of 0?
What about 0.7? -0.7? 0.3? -0.3?

15. Line of Best Fit
A line of best fit (or "trend" line) is a straight line that best represents the data on a scatter plot. This line may pass through some of the points, none of the points, or all of the points

16. Standard
SC.912.N.1.1: Define a problem based on a specific body of knowledge, for example: biology, chemistry, physics, and earth/space science, and do the following:
Use tools to gather, analyze, and interpret data (this includes the use of measurement in metric and other systems, and also the generation and interpretation of graphical representations of data, including data tables and graphs),