Which is the joint relative frequency for school children who plan to attend camp and have swimming lessons?

To find the joint relative frequency for school children who plan to attend camp and have swimming lessons, you would divide the number of children who meet both criteria by the total number of school children surveyed. This value represents the proportion of children who both plan to attend camp and have swimming lessons, giving insight into the overlap of these two groups. If you have specific numbers, you can calculate it directly; otherwise, you can interpret it as a measure of how common this combination is among the surveyed population.