TI84 Wave Generator

This activity is walks you through the steps to perform sine regression for a randomly generated data set using the TI-84.

Step 1: Get some data.

• Go to the Randomized Wave Data Generator and use the form to get some randomly-generated data (check the boxes for more interesting data).
• Your data should be different from every other data set on earth, so copy and paste it to a (spreadsheet or word-processor) file for your later use.

Step 2: Enter the Data into your Calculator.

1. Press Y= and clear the Y1 function.
2. Press STATPLOT (2nd followed by Y=) and choose Plot1.
3. Under Plot1, select On (press ENTER), after Type select the drawing of disconnected dots, and make sure you have Xlist: L1(2nd followed by 1) and Ylist: L2 (2nd followed by 2).
4. Press STAT. With EDIT highlighted, select 1:Edit…
5. In the table that appears, under L1 type the x values and under L2 type the values of y. Make sure your L1 and L2 lists have the same length. (key in the data obtained from the Randomised Wave Generator)
6. Press ZOOM and choose option 9:ZoomStat to look at a scatter plot of your data.

Step 3: Find the Sine Wave of Best Fit for the Data.

1. Press STAT. Press the right arrow key to highlight CALC. Then scroll down to select C:SinReg and pressENTER ONCE.
2. In the SinReg screen, choose Iterations:3 Xlist:L1, Ylist:L2 and Store RegEq: Y1 (press VARS, then select Y-VARS , then select FUNCTION, and then select Y1). Then highlight Calculate and press ENTER ONCE.
3. The calculator should now display the values for a, b, c, and d in the function f(x)=asin(bx+c)+dthat best fits the given data set.
4. Press GRAPH to see the sine regression function plotted along with your scatter plot and press Y1 to see the equation of your wave.

Task: in sub groups of 3s

1. Using the Randomized Wave Data Generator generate a (1) Set of Data.
2. Identify the best fit function f(x)=asin(bx+c)+dthat best fits the given data set
3. Explain the Transformation of your function using f(x)=sin(x) as a bench mark points. Your explanation should be as follows

• Increase in amplitude by a
• period change by ....
• vertical shift by ....