Given:
The standard deviation, σ = 5.
The observed value, X=44.
The z score, z=2.00.
The expression for z-score can be written as,
[tex]z=\frac{X-\mu}{\sigma}[/tex]Here, μ is the mean.
Substitute the known values in the above equation to find mean μ.
[tex]\begin{gathered} 2=\frac{44-\mu}{5} \\ 5\times2=44-\mu \\ 10=44-\mu \\ \mu=44-10 \\ \mu=34 \end{gathered}[/tex]Therefore, the population mean is 34.
