A colleague has been tutoring six students in 11th grade to prepare for the ACT. This colleague has asked you to evaluate the performance of his students. Student scores were as follows: 20, 18, 16, 15, 23, 20. The mean of the ACT scores is: a. 18 b. 20 c. 19 d. 17

We have been given that a colleague has been tutoring six students in 11th grade to prepare for the ACT. Student scores were as follows: 20, 18, 16, 15, 23, 20. We are asked to find the mean of the ACT scores.

We will use mean formula to solve our given problem.  

Upon rounding to nearest whole number, we will get:

Therefore, the mean of the ACT scores is 19 and option 'c' is the correct choice.