Jinfa, upon receiving his paycheck, spent four-fifths of it on car repairs and then bought a $40 gift for his mother. He had $64 left. How much was his paycheck?

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.