A simple random sample of n = 4 respondents yields measurements y = (20, 30, 40, 50) with sample mean $\bar{y} = 35$. Using jackknife variance estimation, the researcher deletes each observation and recalculates: $\bar{y}_{(-1)} = 40$, $\bar{y}_{(-2)} = 36.67$, $\bar{y}_{(-3)} = 33.33$, $\bar{y}_{(-4)} = 30$. The jackknife variance is computed as: $V_{Jack} = \frac{n-1}{n} \sum_{i=1}^n (\bar{y}_{(-i)} - \bar{y})^2$

What is the jackknife variance estimate?