Precision example

In this scenario, two groups of students took the same test.

Group A: On Tuesday 120 students took the test.  All of the scores were within a few points of each other and the average score was 88%.

Group B: On Thursday, 10 other students took the test.  One failed, one got a perfect score, and a few were in the middle. The average score for this group was 75%.

Assuming that the two groups were randomly chosen from the school, which group’s estimated average score is likely to be closer to the true average score for students in this school?