Scatterplots

Using a Graphing Calculator for Line of Best Fit

Question- Draw a scatterplot for the data comparing basketball players shots taken to the number of baskets scored. What conclusions can you make from the scatter plot?

Person	A	B	C	D	E	F	G	H	I	J	K
Shots	64	72	53	79	76	65	61	69	63	80	51
Baskets	18	24	24	30	26	10	18	24	22	26	16

To graph a scatterplot with a TI-83 calculator and determine the line of best fit, complete the following-

1. Use keys STAT - EDIT to access the stats lists and enter the data. Enter Shots in List 1 (L1) and Baskets in List 2 (L2)
2. To prepare the screen to view the graph, we must edit the WINDOW. Change the x values to display up to 100 (the largest number of shots were 80) and the y value to 50 (the largest number of baskets were 30)
3. To set up the scatterplot access the STATPLOT button and set the plot to ON, the type to SCATTERPLOT (the first choice) the Xlist is going to be List 1 and the YList is going to be List 2. Once the appropriate items are highlighted press ENTER.
4. GRAPH. The display should appear as shown. You may TRACE the points by using the TRACE function and the arrows.
5. To determine the line of best fit, press STAT - CALC- LinReg - ENTER
6. ENTER again and we get the linear regression equation, in other words the best fitting line.
7. Using the equation determined in step 6, we can add the line to the graph by accessing the Y= button and entering Y=.345X-1.406
8.GRAPH one more time and the line has been added to the scatterplot. You can use the TRACE function to navigate around the graph.