The rule of the mean is
Mean = sum/number
The given data is
30, 34, 32, 31, 34, 39, 36, 30, 32, 34, 38, 39, 35, 37, 38
There are 15 numbers, then
The number = 15
We will add all of them to find the sum
![\begin{gathered} S=30+34+32+31+34+39+36+30+32+34+38+39+35+37+38 \\ \\ S=519 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/em5raqpw9uoaoyjgf8cdaxxwnygt12euo8.png)
The sum = 519
Then divide it by 15 to find the mean
![\begin{gathered} Mean=(519)/(15) \\ \\ Mean=34.6 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/h0fky5nknv5xc1s3ea432abzdlnu4nlwmc.png)
The mean is 34.6