Justin needs 9 pieces of rope that are 1 1/2 feet long each. He says he can cut the 9 pieces from a 12 3/4 foot long rope. Is Justin correct? Write an equation with a complex fraction to support your answer.

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.