+4 There are 20 students who started precalculus in 11th grade and 20 students who started precalculus in 12th grade. The first group has a mean final grade of 88% and the second group has a mean final scored of 83%. The line plot shows the difference after 15 randomizations. Determine the difference in the means of the two groups and whether the difference of means is significant based on the line plot.
Explain your answer.
