Rosie bought 1 2/5 pounds of cantaloupe. She also bought watermelons that were 3/13 times the weight of the cantaloupes. How much did the watermelons weigh?

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.