A population has mean $\mu$ and variance $\sigma^2$. For a random sample of size $n$, we construct two standardized datasets: $Y_i = \frac{X_i - \mu}{\sigma}$ and $Z_i = \frac{X_i - \bar{X}}{s}$, where $s$ is the sample standard deviation. Which of the following is strictly true regarding the sample variances $s_Y^2$ and $s_Z^2$?