Suppose that you wanted to determine if your eastern region of wholesalers differed from your western region of wholesalers in the proportion of sales that they made to department stores. Your data show that the 80 eastern wholesalers had 40 percent of their sales to department stores, while the 60 western region wholesalers had 25 percent of their sales to department stores. what the pooled estimate of the proportion of sales to department stores is approximately: