Presentation on theme: "Linear Correlation and Regression Using the TI-83 or TI-84."— Presentation transcript:
Linear Correlation and Regression Using the TI-83 or TI-84
Finding “r” and the trend line equation by using the calculator…… Before we begin, make sure that your diagnostic is turned on: Press 2 nd 0 Scroll down to diagnostic on Press Enter twice Temp.Emergency Calls 687 744 828 8810 9311 999 10113
Calculator Steps: Put x’s in L1 and y’s in L2. Press Stat Calc 4:LinReg Vars Y-Vars 1:Function Enter Enter You should see all data.
Correlation Coefficient “r” is equal to.811. The trend line equation is y =.19x – 7.54
In the equation y =.19x – 7.54 a. Explain the meaning of the y- intercept. b. Explain the meaning of the slope. Temp.Emergency Calls 687 744 828 8810 9311 999 10113
Equation: y =.19x – 7.54 A. The number of emergency phone calls when the temp is 0. B. The number of emergency phone calls increases.19 for every degree increase in temperature. (The # of calls/degree temp increase) Temp.Emergency Calls 687 744 828 8810 9311 999 10113
You can also graph it…… The equation for the trend line is now in “y =“. Press zoom 9 to see the scatter plot and the trend line.
You try…… Find: a. Correlation coefficient b.Trend line equation Graph on graphing calculator. Explain the meaning of the y-int and the slope. AbsencesFinal Grade 682 286 1543 974 1258 590 878
Correlation Coefficient: -.944 Equation: y = -3.62x + 102.5
Equation: y = -3.62x + 102.5 Meaning of Y- Intercept: The final grade when a student has 0 absences. (102.5) Meaning of slope: Final grade/absence – the grade decreases (3.62) for every absence made AbsencesFinal Grade 682 286 1543 974 1258 590 878
Example…… Max used linear regression to help him understand the relationship between the temp and the number of ice cream cones sold. The line of best fit was y = 5x + 60, where x is the # of ice cream cones sold and y is the temp in degrees F. In terms of ice cream cones sold and temp answer the following.
Equation: y = 5x + 60 Explain the meaning of the y-intercept: The temperature (60 degree F) when no ice cream cones are sold. Explain the meaning of the slope: The temperature increases 5 degrees F for every ice cream cone sold. (Temp/# sold)
Assignment…… Use ONLY the TI-83 or TI-84 to find the values on the HW assignment.