Answer
$M=4$
$median=4.5$
$mode=5$
Work Step by Step
The mean:
$M=\frac{∑X}{N}=\frac{5+4+5+2+7+1+3+5}{8}=\frac{32}{8}=4$
Scores in ascending order: $1~~2~~3~~4~~5~~5~~5~~7$
Since there are 8 scores ($N=8$), the median is the mean between the 4th and the 5th scores in ascending order:
$median=\frac{4+5}{2}=4.5$
It is clear that the score $5$ has the greatest frequency. So:
$mode=5$
