A grocery store buys cantaloupes from two different farmers. They take a random sample of 64 of these melons from each of the farms. The cantaloupes sampled from the first farm averaged 4 pounds with a standard deviation of 0.5 pounds, while the cantaloupes sampled from the second farm averaged 4.2 pounds with a standard deviation of 0.6 pounds. The standard error for the sampling distribution of the sample average for the first farm is