Presentation on theme: "Linear Correlation and Regression"— Presentation transcript:
1Linear Correlation and Regression Using the TI-83 or TI-84
2Finding “r” and the trend line equation by using the calculator…… Temp.Emergency Calls6877448288810931199910113Before we begin, make sure that your diagnostic is turned on:Press 2nd 0Scroll down to diagnostic onPress Enter twice
3Calculator Steps:Put x’s in L1 and y’s in L2.Press Stat Calc 4:LinReg Vars Y-Vars 1:Function Enter EnterYou should see all data.
4Correlation Coefficient “r” is equal to .811. The trend line equation is y = .19x – 7.54
5a. Explain the meaning of the y-intercept . Temp.Emergency Calls6877448288810931199910113In the equationy = .19x – 7.54a. Explain the meaning of the y-intercept .b. Explain the meaning of the slope.
6Equation: y = .19x – 7.54Temp.Emergency Calls6877448288810931199910113A. 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)
7You can also graph it…… The equation for the trend line is now in Press zoom 9 to see the scatter plot and the trend line.
8You try…… Find: a. Correlation coefficient b. Trend line equation Graph on graphing calculator.Explain the meaning of the y-int and the slope.AbsencesFinal Grade68228615439741258590878
11Equation: y = -3.62x + 102.5 Meaning of Y-Intercept: AbsencesFinal Grade68228615439741258590878Meaning 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
12Example……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.
13Equation: 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)
14Assignment……Use ONLY the TI-83 or TI-84 to find the values on the HW assignment.