im doing a graph for chem lab with excel.
my classmate created a graph with these coordinates:
X:
3.50 X10^-3
3.14X10^-3
3.28X10^-3
Y:
-11.7
-8.96
-9.75
They got R2=0.998 but i got y = -3074.9x
R² = 0.6291
why is it wrong. im desperate please help!
screen shot of my graph:
img530.imageshack.us/img530/7507/grph.jpg
I've graphed those values in Excel and then compared it to your image.
The graphs are the same, and my R2 value is closer to your friend's value.
Basically, your trendlines are different; the scatterplots are same.
You must have set the intercept to 0.0 along with checking off Display Equation and Display R-squared value. If your professor has required that you have the trendline cross the y-axis, then your graph is correct (and your lab partner has just forgotten to Set Intercept for her trendline)