An internet service provider (ISP) provides internet connections to 100,000 customers. 10,000 of the customers have high-speed connections and 90,000 of the customers have low-speed connections. The ISP wants to know whether, on the average, customers who have high-speed connections use email more frequently than customers who have low-speed connections. To find out, the ISP takes a simple random sample of 350 high-speed-connection customers and an independent random sample of 400 low-speed-connection customers. For each customer in the sample, they find the number of email -messages sent and received in the previous month. Then