The Use of Statistic: My Grades

I've noticed that my grades are steadily falling as the year progresses.Here's a breakdown...:

	1st	2nd	3rd
Latin	98.1	93.9	90
Pre-Calc	101.8	92.6	96.6
Stats	96	98	93
Physics	99.3	94.7	92.6
Band	98.4	94	94
Chem	101	96	94
English	98	94	95

If I remember correctly in middle school, I always get awful grades the first nine weeks, improve the second, peak at my third, and fall my fourth. Alas, now I've gotten the habit of hitting the road running with not enough gasoline to power through the whole year.



Running a simple linear regression test showed that I indeed have a negative correlation of -.749 with a r-squared value of .561, meaning 56.1% of all my change in grades is determined by the nine-weeks. A look at the graph with the regression line (y = 101.1047 - 2.6714x, my y-intercept is an amazing 101.1047...haha) in: 

A look at the residual plot shows nothing really weird going on... there's not that much data to confirm a curved shape.

A box-plot of the residuals look relatively normal, no outliers and random stuff:

Okay... now I can run a linear regression t-test. Hmm, I don't think I did this right, but with a t-score of -4.927 with df = 19, makes the p-value close to zero. 


Guess that's not significant then....


-runiteking1
 

Got comments? Post them below!