Twelve boys collected 16 aluminum cans each. fifteen girls collected 14 aluminum cans each. how many more cans did the girls collect than the boys

Find the value of the cosine for angle a

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.

Ineed the solution to this problem and the steps.