Use your calculator to draw a scatter plot of the data.
Example model: y=4.47x+12.99 Example estimate: 26.4 years
Practice makes perfect
Let's use the calculator to draw a scatter plot of the data.
Push the STAT button, choose Edit, and enter your values.
Once the values have been entered we can plot them by pushing 2nd, and Y=, then choosing one of the plots in the list. Make sure you turn the plot ON before you choose the scatter plot type. Then, match the lists for the x- and y-values accordingly.
By pushing GRAPH the calculator will plot the data. Note that we will need to change the viewing window so that we can see all of the points.
We can see that apart from the first data points the trend is linear, so let's use a linear regression.
We can access this option by pressing the STAT button and choosing LinReg(ax+b) from the CALC menu.
After matching the lists for the x- and y-values and storing the equation, move to the last line and press ENTER.
The result screen gives the coefficient of the linear model.
y= ax+ b
⇓
y= 4.47x+ 12.99
Since the regression equation is now stored in the memory of the calculator, when we press GRAPH again we can see the regression line with the scatter plot.
We can use the calculator to estimate the age (in human years) of a cat that is 3 years old.
Push 2nd and TRACE, choose value from the menu, and set x=3.
We can also check this result by substituting x=3 in the regression equation.
