Answer:
There is not enough evidence to support the claim that the scores after the stats course are significantly higher than the scores before (the difference in the scores is higher than 0).
P-value=0.042.
Step-by-step explanation:
The question is incomplete:
The data of the scores for each student is:
Before    After
430        465
485        475
520        535
360        410
440        425
500        505
425        450
470        480
515        520
430        430
450        460
495        500
540        530
We will generate a sample for the difference of scores (before - after) and test that sample.
The sample of the difference is [35 -10 15 50 -15 5 25 10 5 0 10 5 -10]
This sample, of size n=13, has a mean of 9.615 and a standard deviation of 18.423.
The claim is that the scores after the stats course are significantly higher than the scores before (the difference in the scores is higher than 0).
Then, the null and alternative hypothesis are:

The significance level is 0.01.
The estimated standard error of the mean is computed using the formula:

Then, we can calculate the t-statistic as:

The degrees of freedom for this sample size are:

This test is a right-tailed test, with 12 degrees of freedom and t=1.882, so the P-value for this test is calculated as (using a t-table):

As the P-value (0.042) is bigger than the significance level (0.01), the effect is  not significant.
The null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the scores after the stats course are significantly higher than the scores before (the difference in the scores is higher than 0).