Two random samples are selected from two independent populations. A summary of the samples sizes and sample means is given below:

$$\begin{array}{ll} n_1 = 37, & \bar{x}_1 = 51.8 \\ n_2 = 46, & \bar{x}_2 = 77.9 \\ \end{array}$$

If the 93% confidence interval for the difference $\mu_1 - \mu_2$ of the means is (-29.6639, -22.5361), what is the value of the pooled variance estimator? (You may assume equal population variances.)

Pooled Variance Estimator =