A person bought some cosmetic from wholesale market at the rate of Rs 360 per dozen he sells it at rs 80 a pair. find the gain percent with explanation ​

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.