Answer: The required mean score is 73.93.
Step-by-step explanation: We are given to find the mean score for Mr. Wilson's test scores.
We know that
the mean of a given set of scores is equal to the sum of the scores divided by the number of students who scored the marks.
From the given information, we have
3 students with score 40, 1 student with score 50, 4 students with score 60, 6 students with score 70, 4 students with score 80, 8 students with score 90 and 2 students with score 100.
Therefore, the MEAN score of Mr. Wilson's test scores is given by
![M\\\\\\=\dfrac{3\times40+1\times50+4\times60+6\times70+4\times80+8\times90+2\times100}{3+1+4+6+4+8+2}\\\\\\=\dfrac{120+50+240+420+320+720+200}{28}\\\\\\=\dfrac{2070}{28}\\\\=73.93.](https://tex.z-dn.net/?f=M%5C%5C%5C%5C%5C%5C%3D%5Cdfrac%7B3%5Ctimes40%2B1%5Ctimes50%2B4%5Ctimes60%2B6%5Ctimes70%2B4%5Ctimes80%2B8%5Ctimes90%2B2%5Ctimes100%7D%7B3%2B1%2B4%2B6%2B4%2B8%2B2%7D%5C%5C%5C%5C%5C%5C%3D%5Cdfrac%7B120%2B50%2B240%2B420%2B320%2B720%2B200%7D%7B28%7D%5C%5C%5C%5C%5C%5C%3D%5Cdfrac%7B2070%7D%7B28%7D%5C%5C%5C%5C%3D73.93.)
Thus, the required mean score is 73.93.