Investigating Scatter Plots You will need a lined sheet of paper to answer the numbered questions in the PowerPoint

Investigating Scatter Plots Scatter plots are similar to line graphs in that each graph uses the horizontal ( x ) axis and vertical ( y ) axis to plot data points. The dots are not connected on scatter plots. Scatter plots are most often used to show correlations or relationships among data.

Investigating Scatter Plots Positive correlations occur when two variables or values move in the same direction.  As the number of hours that you study increases your overall class grade increases 1) Give another example of two variables that have positive correlation

Investigating Scatter Plots – Positive Correlation Notice how the general pattern of the graph is uphill or increasing

Investigating Scatter Plots Look at the data in the table. 2) Are the x values increasing or decreasing? 3)Are the y values increasing or decreasing? 4)Plot the points online and sketch your graph on your lined paper 5) What type of correlation do you see? 6) Why can positive correlation be seen when both values decrease? x5431 y5320-2

Investigating Scatter Plots Negative Correlations occur when variables move in opposite directions  As the number of days per month that you are absent increases your overall grade decreases 7) Give an example of two variables that have negative correlation (in general)

Investigating Scatter Plots – Negative Correlation Notice how the general trend of the graph is decreasing

Investigating Scatter Plots No correlation exists if there is no noticeable pattern in the data  There is no relationship between the number of shirts someone owns and their annual salary 8) Give another example of 2 variables that have no correlation (in general)

Investigating Scatter Plots – No Correlation There is no pattern in the data when it is graphed

Investigating Scatter Plots 9) Tell the type of correlation and the relationship between the two variables in the graph below

Investigating Scatter Plots 10) Tell the type of correlation and the relationship between the two variables graphed below

Scatter Plot Practice Go to the site and play the game us/math_games/data/representing_data/scatter_pl ots 11)Write 3 sentences about the game.

Line of Best Fit A line of best fit is a line that best represents the data on a scatter plot. A line of best fit may also be called a trend line since it shows us the trend of the data  The line may pass through some of the points, none of the points, or all of the points.  The purpose of the line of best fit is to show the overall trend or pattern in the data and to allow the reader to make predictions about future trends in the data.

Line of Best fit A good line of fitA not so good line of fit

Practice Line of Fit Go to this site and play the game ay&gameid=121 12) Write 3 sentences about the game

Scatter Plot Quiz Go to this site and take the quiz. Write your answers on the lined paper 13)Write 1 sentence about the quiz. Include your score. Go to this site and complete the eWorkbook for Chapter 5 Section 6. There are some questions that the images don’t show up for; please skip those questions. Write your answers on the lined paper. 07_na/book_home.htm?state=MI 14) Your answers to the eWorkbook problems

The original creator of this PowerPoint is Mr. J. Miles