Answer :
Given:
The total number is 50.
A set of 50 numbers consists of nine 7s, ten 8s, twelve 9s, ten 10s, five 11s, and the remainder were 12s.
Required:
To find the mean.
Explanation:
Here nine 7s, ten 8s, twelve 9s, ten 10s, five 11s, and the remainder were 12s.
So the remaining number is
[tex]\begin{gathered} =50-(9+10+12+5) \\ =50-36 \\ =14 \end{gathered}[/tex]Now the mean is
[tex]\begin{gathered} =\frac{9\times7+10\times8+12\times9+5\times11+14\times12}{50} \\ \\ =\frac{63+80+108+55+168}{50} \\ \\ =\frac{474}{50} \\ \\ =9.48 \end{gathered}[/tex]Final Answer:
The mean is 9.48