It was determined that, in a class of 25 students, the mean score on a chemistry test was \( 67 \% \). A new student joined the class one week later and sat the same test. He achieved a score of \( 95 \% \). a. Would this new score increase or decrease the mean value? b. Calculate the new mean score, rounded to one decimal place.

To determine whether the new score would increase or decrease the mean, let's first consider the total scores of the original 25 students. The total score can be calculated as: \[ \text{Total score of original 25 students} = \text{Mean} \times \text{Number of students} = 67\% \times 25 = 1675 \] Now, with the new student scoring \( 95\% \), the new total score becomes: \[ \text{New total score} = 1675 + 95 = 1770 \] Now, with 26 students in total, we can calculate the new mean score: \[ \text{New Mean} = \frac{\text{New Total Score}}{\text{Number of Students}} = \frac{1770}{26} \approx 68.1 \] To answer the questions: a. The new score will increase the mean value. b. The new mean score is approximately \( 68.1\% \).